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7.62 NATO and .308 Winchester

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Topic: 7.62 NATO and .308 Winchester
Posted By: Smokey
Subject: 7.62 NATO and .308 Winchester
Date Posted: October 11 2009 at 6:11am
The WWII .30-06 M2 Ball specifications required 835 m/s (2,740 feet per second) velocity, measured 24 m (78 ft) from the muzzle. Muzzle velocity was 2,805 ft/s.
The 7.62 NATO does close to the same with a smaller cartridge.
I believe the M2 Ball operated with a peak pressure of around 45,000 PSI. The NATO cartridge peaks at about 50,000 psi to get the same velocity. .308 Winchester ammo can run much higher, with a maximum of 62,000 psi. I would not want to run any "regular" No.4 Mark1 or 2 with ammo at those pressures. Headspace will be increased. The Indian rifle uses a higher-strength steel for the action to handle the NATO cartridge, but again I'd stay away from the non-NATO ammo.
In any event, reloading allows the use of milder loads that extend the life of your rifle.



Replies:
Posted By: Stnwll2
Date Posted: October 11 2009 at 7:25am
What I don't understand about the whole 308/7.62 issue is ..... Isn't it essentially a physics problem?

Given the same weight projectile and the same velocity shouldn't the pressure be the same out of the same rifle?

147/150 grain FMJ bullet moving at about 2800 fps.  Doesn't that math problem give you the same pressure assuming the same rifle?

Why should it take more pressure to move the .308 than the 7.62?  If the .308 developed more pressure shouldn't the velocity be significantly higher too?

I stood in the ammo isle of the local Sportsman's Warehouse looking at all the .308 ammo, with 150 gr slugs and heavier and all of them had roughly the same velocity listed.  I can see that the heavier bullets may require higher pressure.

I have a degree in History so there very well could be a math subtlety that I'm missing.


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Catapultam habeo. Nisi pecuniam omnem mihi dabis, ad caput tuum saxum immane mittam.


Posted By: Shamu
Date Posted: October 11 2009 at 10:03pm
Hoo Boy! Get the popcorn, this may take a while.Confused
 
The .308 Winchester is the civillian version of the 7.62mm NATO round.
There are minor tolerance differences in the spec drawings for the 2 cases.
 
The 7.62mm NATO round is frequently made with thicker brass (to better handle the violent cycle of full auto weapons.)
 
SAAMI use one method to measure pressure during firing & NATO use a different method that uses a different unit of measurement. Because of this & several other things there is a lot of confusion about the actual pressures generated during firing the 2 rounds in an identical chamber.
 
Because of the thicker brass with the same external dimensions the volume inside the 2 cases differs. IF you're reloading you need to lower the charge weights to allow for the lower internal volume.
Also there are some rifles that won't run well with some commercial loads (The Garand being a major example).  The Garand's design has an inherant weakness. Ithe dog leg operating rod can be bent with heavy bullets & slow-burning powders! Not a defect for military use as the medium speed powder & 150 gr bullets worked perfectly, but if you were to load say a 220 gr bullet with a slower burning powder you'd have a problem.
 
Powders vary as well. the same volume of unburnt powder gan produce differnt volumes of gas, and at different speeds. Because of this there is a curve of pressure because "gunpowder" doesn't "explode" it burns fast. The peak of the curve can create temporary pressures that are above the safe limits for the case & action.
 
The 2 methods of measuring pressure come into play here.
One measures only the total effect of the pressure at the end of the cycle. The other actually measures & graphs the curve in real time as it happens.
 
As you can imagine this gets slightly different answers to the same question. Now throw in for luck the differences in the units of measurement & add the fact that one is called "PSI" but is NOT "Pounds Per Square Inch" & the source of confusion becomes easy to understand.


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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: Edward Horton
Date Posted: October 12 2009 at 7:12am
< ="-" ="text/; =utf-8"> < name="GENERATOR" ="Office.org 3.0 Linux"> < ="text/"> < ="-" ="text/; =utf-8"> < name="GENERATOR" ="Office.org 3.0 Linux"> < ="text/">

Did you ever hear anyone say if you shoot commercial 30-06 ammunition in a military 03-Springfield your Springfield 03 would blow up?

The rumor mill started about the .308/7.62 and chamber pressures because some people do not understand the difference between the older copper crusher method and the newer transducer method of measuring chamber pressure.

On top of this the military manuals use the older copper crusher method and list the chamber pressure in PSI.....BUT remember it is in the older CUP (copper units pressure) which is also read as PSI or pounds per square inch, NOT to be confused with the transducer method which is also read as PSI.

What you need to realize is 50,000 CUP is equal to 60,000 PSI just as 60 MPH is equal to 100 KPH. On paper there is actually less than 200 PSI difference between the .308 Win and the 7.62 NATO which is insignificant. In reality the .308 actually generates LESS pressure than the 7.62 NATO because the American ammunition manufactures load there ammunition below the maximum allowed chamber pressures.

In closing as you can see below if put 220 kPa in your tires they will blowup and kill everyone in a 50 yard radius, but if you only put 32 PSI in your tires you will be perfectly safe and your tires will not blow up. Wink



Posted By: Cookie Monster
Date Posted: October 12 2009 at 7:12am

There is several post on this topic if you wish to search for them. Ask Tony he has archived many of these



Posted By: Stnwll2
Date Posted: October 12 2009 at 1:26pm
Soooooo ....

The fact that My 1965 2A1 didn't blow when I shot 20 rounds of American Eagle 308 though it shouldn't surprise me. 150gr, 2780 fps (-ish) .... about the same as Nato.

Beer


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Catapultam habeo. Nisi pecuniam omnem mihi dabis, ad caput tuum saxum immane mittam.


Posted By: Tony
Date Posted: October 12 2009 at 3:12pm
There have been arguments on other forums regarding pressures and Nato ammunition and I'm not getting involved in an argument on here. All I will say is comercial ammo is made to suit MODERN rifles which haven't been ill used they are of a stronger construction using modern steel and different bolt locking formats. The forum doesn't take ANY responsibility for anybody using ammunition of their choice in their weapons.The archive material has been posted as a guide read it then make your own decisions.You should all have loading data from a reputable source email Hornady, Sierra, Lynman or Vhitavuouri and ask their advice! Don't rely on an "internet expert ". The above make ammunition or powders etc THEY are the experts.


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Rottie (PitBulls dad.)


“If electricity comes from electrons, does morality come from morons

Born free taxed to death!!!



Posted By: Tony
Date Posted: October 12 2009 at 9:56pm
As Disraeli said there are lies Dammn lies and statistics. Stats can be bent to suit any circumstance so ASK THE EXPERTS! 

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Rottie (PitBulls dad.)


“If electricity comes from electrons, does morality come from morons

Born free taxed to death!!!



Posted By: Edward Horton
Date Posted: October 13 2009 at 12:52am
< ="-" ="text/; =utf-8"> < name="GENERATOR" ="Office.org 3.0 Linux"> < ="text/">

The Truth About 308 Win and 762 NATO


A little info that some people might find interesting that is not over exaggerated or based on urban myth.


The Truth About 308 Win and 762 NATO

http://home.comcast.net/%7Eehorton/The%20Truth%20About%20308%20Win%20and%20762%20NATO.pdf - http://home.comcast.net/~ehorton/The...d 762 NATO.pdf


Is it safe to shoot 308 Winchester in a rifle chambered for 7.62 NATO?
What about 7.62 in a 308?
By Jim Bullock

http://www.smellysmleshooters.net/ammopressure.htm - http://www.smellysmleshooters.net/ammopressure.htm




Posted By: Edward Horton
Date Posted: October 13 2009 at 1:05am

Pressure convershion chart CUP to PSI




The U.S. Army manual is written in CUP (copper units pressure) BUT it still is read as PSI or pounds per square inch, the pressures given below are not in the newer transducer method which are also read as PSI.



Posted By: Tony
Date Posted: October 13 2009 at 4:03am
 You're the person involved in the argument on the other site aren't you?? You wound up the other members!! I suggest you read your own links RE WEAPONS IN GOOD ORDER. As I said in my first reply we do NOT know if the weapons any of our members is using has been abused prior to the member purchasing it.ERGO THE FORUM DOES NOT ACCEPT RESPONSIBILITY FOR ANY MEMBER USING UNSUITABLE AMMUNITION IN THEIR WEAPONS!


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Rottie (PitBulls dad.)


“If electricity comes from electrons, does morality come from morons

Born free taxed to death!!!



Posted By: Shamu
Date Posted: October 13 2009 at 4:07am
Originally posted by Stnwll2 Stnwll2 wrote:

Soooooo ....

The fact that My 1965 2A1 didn't blow when I shot 20 rounds of American Eagle 308 though it shouldn't surprise me. 150gr, 2780 fps (-ish) .... about the same as Nato.

Beer
YupClap
What you've discovered is the difference between the real world, where bumble bees buzz happily hither & yon, & the thoeretical world where the bumble bee is incapable of flight, mathematically speaking.Wink


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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: Edward Horton
Date Posted: October 13 2009 at 4:26am
< ="-" ="text/; =utf-8"> < name="GENERATOR" ="Office.org 3.0 Linux"> < ="text/">

Tony you are a moderator, since when is posting published facts to clear up confusion and stupidity considered stirring up the natives or making trouble.


I have NO idea what you are talking about in your above posting or are all moderators as insulting as you are in this forum. Your above posting smells of “burn the witch or “off with his head” for presenting proven facts instead of rumors.


IF you can PROVE that any of the material I have posted here is incorrect then please present facts to the contrary otherwise save your insults for a PM instead of an open forum.



Posted By: Tony
Date Posted: October 13 2009 at 4:51am
My comment is simple! We do not accept responsibility for persons using ammutniton unsuitable for their weapon! Your post states weapons in GOOD order THAT IS THE POINT I AM MAKING! As a moderator I have a responsibility for the safety of the forum members!
 TO AVOID ANY FURTHER PERSONAL ATTACKS I AM LOCKING THE SUBJECT!

Published facts! http://www.surplusrifle.com/shooting2006/308vs762nato/index.asp - http://www.surplusrifle.com/shooting2006/308vs762nato/index.asp

-------------
Rottie (PitBulls dad.)


“If electricity comes from electrons, does morality come from morons

Born free taxed to death!!!



Posted By: Cookie Monster
Date Posted: October 13 2009 at 6:16am
Enough is enough lets resolve this in a civil manner whan is a good time to discuss this in the chat room. Let me know what is a good time ?


Posted By: Tony
Date Posted: November 03 2009 at 7:24pm
Ok GENTLEMEN I have unlocked this thread now things have calmed down. I'll be keeping a watchful eye on things in here as well as the forum in general.

-------------
Rottie (PitBulls dad.)


“If electricity comes from electrons, does morality come from morons

Born free taxed to death!!!



Posted By: Alan de Enfield
Date Posted: November 04 2009 at 12:54am
Whilst 308 and 7.62 may look the same, in fact (as has already been said) the NATO cases are thicker brass and hence have less space inside, a similar amount of powder in a 7.62 will have less space than in a 308 and hence the pressures will be considerably different, add to this the fact that NATO 7.62 chambers are a different size to commercial 308 and all sorts of problems can occur.
 
Put a 308 cartridge into a 7.62 chamber and you've immediately increased your headspace by 0.013" (13 thou)
 
If it says 7.62 on the rifle use 7.62, if it says 308 use 308.
 
"Use what it says on the tin"


Posted By: oldbikewrench
Date Posted: November 04 2009 at 11:49am
I am not a ballistician so I can't get all technical, but I bought a CETME a little while back and was told that yes it would shoot off the shelf .308 Winchester ammo. Well it did indeed fire one round and that case was perfectly fire formed. And for those that don't know, the CETME has a fluted chamber. That case was really stuck in there. Had a heck of a time getting it out.


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Love your neighbor as yourself.'...Mark12:31
He said to them, "But now if you have a purse, take it, and also a bag; and if you don't have a sword, sell your cloak and buy one. Luke22:36


Posted By: Unauthorized
Date Posted: November 04 2009 at 12:00pm
The Brits sanction the use of #4s with only one 7.62 load the 144 grn Nato version.



Posted By: Shamu
Date Posted: November 04 2009 at 10:30pm
While agreeing with the point raised on brass thickness having the side effect of reducing internal volume this can simply be compensated for by using an appropriate powder charge for that volume.
This is a basic re loading technique with any brass, or caliber.
 
When all the measurements are taken & compared & all the thoeries are expounded on there is still one question that no-one who is a suppoerter of the "It's different" train of thought have been able to answer for me personally, so I'll ask it again.
 
IF there is a real, functional difference between MilSurp 7.62mm NATO, & .308 Winchester commercial ammunition why is it that I've been able to fire both factory-issued ammunition & my own reloads in both commercial .308 Winchester & 7.62mm NATO chambers with complete interchangability for the last 15 years without incident, regardless of the combination used?
 
This would seem to indicate that real problems regarding complete functional interchangability do not exist.


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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: Unauthorized
Date Posted: November 24 2009 at 12:37am
Were any of your rounds actually fired in a converted #4 Lee Enfield?

Rifles designed for either round would probably be ok.
The #4s are approved by the Bits only of the 144 grn 7.62 Nato load. They were not designed for either round.


Posted By: Alan de Enfield
Date Posted: November 24 2009 at 1:09am
Originally posted by Unauthorized Unauthorized wrote:

Were any of your rounds actually fired in a converted #4 Lee Enfield?

Rifles designed for either round would probably be ok.
The #4s are approved by the Bits only of the 144 grn 7.62 Nato load. They were not designed for either round.
 
The UK NRA did indeed issue a warning regarding the use of heavier than 144 gr 7.62 bullets in converted NO4 actions - stating that there was risk of catastrophic failures.
Here is a 'cut and paste' of the warning.
 
NRA Safety Warning
Enfield Rifle Actions Converted to 7.62 Calibre from .303 or made as 7.62 mm. Enfield actions of the No 4 and No 5 type were originally designed to fire the British .303 service cartridges of the day.
Many of these actions have been subsequently converted from .303 to 7.62 mm. Whilst a few selected actions may be stronger than others, most are not suitable for use in this calibre other than under certain conditions.
The 7.62 mm Cartridge that they were intended to use was the 144-grain NATO cartridge with a bullet diameter of .3075".

It is unsafe to fire these rifles with the 155 grain Radway Green cartridge or any other commercial cartridges using the 155 grain or heavier bullet which has a diameter of .3083" or larger.

 Firing these latter cartridges can ultimately lead to catastrophic failure of the bolt lugs and bolt body that could lead to serious injury. This risk is considerably increased if the chamber or cartridge gets wet or is oiled prior to firing.

The NRA will not accept responsibility for any accident or injury to persons or property caused by anyone using any 7.62 / .308 Win ammunition supplied by them in these converted actions.

The actions/rifles involved the following descriptions,but ther may also be other names or descriptions,SMLE Conversion,Enfield Conversion,No4 Conversion, No 5 Conversion,Parker Hale T4,Whitaker Special, Enfield Envoy and Enfield Enforcer

 
I have heard (no confirmation) that under the threat of legal action the NRA has been forced to withdraw that statement as they can offer no evidence of any kind to support their claim. (The notice has certainly been removed from Bisley)
 
Again - speculation, but it is thought that an NRA 'official' read something on the internet and took it as 'gospel'.


Posted By: LE Owner
Date Posted: December 04 2009 at 7:45am
Perhaps this will shed light on the warning which seems to be directed at those rifles fitted with barrels tighter than the more common .308 dia.
 
http://www.triplej.com.au/pdfpages/pressure_factors.pdf - http://www.triplej.com.au/pdfpages/pressure_factors.pdf
 
The early manufacture FN FAL barrels in British service also had exceptionally tight bores, the reason given was to greatly increase bore life.
Those barrels are said to have been about one thousandth smaller (perhaps less) in land to land and groove to groove measurements. Apparently the British manufacture 144 gr ball used a bullet suited for the tighter bore, later 7.62 ammo types appear to be less suited to the tight bores and can result in significant increase in pressures when fired in a tight bore. 
 
The difference between 7.62 NATO ball and the hottest .308 loads is much like the difference between the .38 ACP and the .38 Super Auto, or the 9mm Glisenti vs the 9mm Parabellum. Dimensionally they are twins, but not all guns manufactured for the earlier cartridge can handle the pressure of the later cartridges.
 
The No.4 Enfield was not manufactured in 7.62 NATO caliber, it was converted to that chambering to use the NATO standard ball, which generates 48,000 CUP or 50,000 PSI Epvat.
The Indian 2A rifle was manufactured in 7.62 NATO, the Indian 7.62 Ball (India is not a NATO member) also generates the same pressures, circa 48,000 CUP or 50,000 PSI.
So long as your rifle is in good order and you chose your ammunition wisely there should be no problems, there are many .308 loads which are at or below 48,000 CUP or 50,000 PSI, but there are also loads which exceed this pressure range by 10% or more.
 
When bullets heavier than 150 gr are used with either 7.62 or .308 the maximum standard deviation in pressures can skyrocket. A 175 grain Special ball cartridge rated at 52,000 CUP has a Max Std Dev of 57,000 CUP 18% higher pressure than the operating pressure of Nato ball.
 
 
PS
Other similar cartridge and rifle combinations would be
The 1895 Winchester in .30/06 caliber, safe enough when cartridges generating pressures no higher than the original 150 gr bullet WW1 era load is used, but long noted for developing excessive headspace when the later 172 gr and WW2 era Ball ammunition and commercial sporting rounds of similar pressure levels were used.
 
The Gew 1888 in "8mm Mauser" chambering, safe enough when pre WW1 8mm ( J bore .318 bullet , .321 bore) cartridges loaded with bullets of .318 to .321 are used, and considered reasonably safe for use with the medium pressure Remington 8mm Mauser sporting ammo (loaded with the .321 bullet developed for the .32-49 and .32 Winchester special) is used, but not so safe when 7.92 S bullet (.323) cartrdges loaded to WW1 and later pressure ranges, and a disaster in waiting should a WW2 era 7.92 Heavy Ball MG or LMG cartridge be used.
Some of these rifles were modified with .323 bores, but even then the metalurgy is suspect and the rifle is not considered suitable for the later Mauser cartridges.
Chambers are the same and cases are pretty much indistinguishable.
 
 


Posted By: Alan de Enfield
Date Posted: December 04 2009 at 4:03pm

 
I have no knowledge on this subject so could not comment - however I do not see the relevance of this statement on a thread about 7.62 Vs 308.
 
Any personal 'attacks' should be removed by the moderators before the battles commence.


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Its not what you've got thats important, its what you hav'nt got, but still want, thats important.


Posted By: LE Owner
Date Posted: December 04 2009 at 4:52pm
While Norton's portrayal of David Banner in the most recent big screen version of the Hulk was uninspired and left much to be desired I would not go quite that far.


Posted By: Tony
Date Posted: December 04 2009 at 5:55pm
I suggest you delete your comment charly45 or I'll do it for you!

-------------
Rottie (PitBulls dad.)


“If electricity comes from electrons, does morality come from morons

Born free taxed to death!!!



Posted By: SW28fan
Date Posted: December 05 2009 at 3:58am
We really don't need personally attacks hear.  I would be happy to see this thread vanish but the Issue of CUP vs PSI has come up.  I once asked a co-worker who is both a shooting enthusiast and  a PhD in metallurgy what is the difference between them and is there a conversion.  The short answer is  they are different animals and not parallel running scales. The conversion is somewhat complicated.  Since simple Triginometry is the absolute zenith of my mathamatical ability I did not press further. The point is that a difference of 2000 in CUP can mean a great deal of pressure.

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Have a Nice Day
If already having a nice day please disregard


Posted By: LE Owner
Date Posted: December 05 2009 at 6:18am
If what I've read on the subject is correct, and I didn't misread it which is a possibility, the US method of measuring chamber pressure by CUP may have been developed by the French in the late 19th century.
The British base thrust method is aimed at determining the actual back thrust to the breech face of cartridges in the dry condition and when cases are lubricated, The British method in use while the Enfield was still a battle rifle does not read actual chamber pressures but rather back thrust in long tons.
The French and US Ordnance methods read Chamber pressures at a chosen spot on the cartridge case or by direct gas inpingement by means of gas bled off at the case mouth to drive the piston. The ammunition being first heated for a period of time to mimic cartridges left in a chamber already warmed by having fired a number of rounds.
The best figures I've found for the British MkVII cartridge as measured in CUP by the US Ordnance method is 45,400 CUP at 60 degrees, I found this information in an article on the P-14 rifle in the Journal of the Franklin Institute, quoted from a book written by a US Ordnance Officer.
In general CUP figures found in manuals are rounded to the nearest 1000, thus the commonly published figure of 45,000 CUP.
 
The more modern EVPAT test figures used for NATO spec ammunition are taken using a piezo electric crystal and expessed as PSI.
Ammunition types not commonly interchangable may not be measured by the EVPAT method, so we have Long range Special Ball measured by the older Copper Units of Pressure.
Standardized 7.62 NATO Ball in US inventory is measured by both the EVPAT and CUP methods, both figures are given in some government publications. Unfortunately some less informative manuals don't make the distinction and this can lead to confusion.
 
The 7.62X51/.308 cartridges have features which can make chamber pressures a bit more critical where heavier bullet long range Match or Sniper ammunition is concerned.
The limitations on OAL of the cartridge, its short OAL being a major design feature, result in longer heavier bullets taking up space in the powder space, effectively reducing available case capacity and resulting in higher pressures to achieve the same performance as a similar load in a cartridge with greater OAL.
When first adopted the intention was to benefit from advances in propellant technology to allow the shorter cartridge to equal the performance of the earlier loadings of the .30/06 without any noticable increase in pressures. This they managed to achieve but only in loads that used bullets of 144-150 grains or less. When heavier bullets are used pressures begin to climb compared to the .30/06 or the .303 for that matter.
When case capacity is restricted by the protrusion of the base of the bullet into the case the normal situation of deviations in maximum pressures are agravated.
 
Add to the above the simple facts that ammunition is declared surplus for the following reasons, over production, obsolesnce, failure to pass the now standard five year inspection of NATO ammunition stocks.
The 7.62 may be less commonly used by infantry rifles than before, but it is far from being obsolete and millions of rounds are being eaten up by GPMGs the world over. Over Production is not an issue since every available round that can pass inspection is needed either for combat or as reserve stock or given to allies. That leaves failure to pass inspection.
So when you seen 7.62X51 ammo sold as surplus these days it almost certainly came from a lot which failed its five year inspection process, and may well have failed that inspection decades earlier and suffered even more degradation from poor storage since then.
Rather than the ammo having one or two cartridges per thousand that develop the maximum deviation of 57,000 CUP a degraded lot might far exceed that figure at every shot from a twenty round box.
In worst case scenario all those variables might combine and a rifle could be subjected to excessive pressures at every shot through hundreds of rounds in a short time.
 
When looking up info on the Enforcer Police sharpshooter rifles I found that the British MOD had at one time released a number of L42 Sniper rifles for police use. These rifles were inspected by the police and found to be dangerously degraded and judged unsafe to fire. The L42 should have been the one converted No.4 action rifle least likely to have suffered such degradation in service. sniper rifles seldom fire as many shots in anger during their entire service life than an infantry rifle might fire in one week of a WW2 campaign.
The L42 should have also been fed only the best available of the approved ammunition type, the 144 gr ball.
Asking a recognized authority on these rifles about the ammunition approved for use with the L42 resulted in no useful information at all. A simple question, one that should have taken only a few words to answer, appeared to generate hostility out of proportion to the subject. In the end no answer other than a vague prohibition against use of non military ammo was given.
 
If ammunition other than the 144 gr ball was used with the L42 towards the end of its service life this might explain those abused rifles the British police depts turned down.
 
I also ran across a discussion on a British military 7.62 ammunition type which has the designation L42 , but which was not in fact meant for use by the L42 rifles. Perhaps a mix up had resulted in an unsuitable ammunition being issued with those rifles, and damage to the actions was the result.
 
 
PS
The major stumbling block to finding out anything useful about the converted No.4 rifles seems to be the emotional attachment some owners and former servicemen have towards the Enfields.
As far as I'm concerned emotional attachments are best reserved for living things.
 
When emotions and personality conflicts intrude any chance of calm discussion and judgements based on fact go out the window.
 
 


Posted By: Tony
Date Posted: December 05 2009 at 6:22am
I have deleted the personal comment made on here! I suggest every member plays nicely or I WILL lock this forum again once and for all.
         Tony.


-------------
Rottie (PitBulls dad.)


“If electricity comes from electrons, does morality come from morons

Born free taxed to death!!!



Posted By: Shamu
Date Posted: December 05 2009 at 7:07am
Let me try to clarify things a bit here.
There are basically 2 seperate issues being mixed together, & this is adding fuel to a burned out fire.
 
1. There is zero practical difference between correctly loaded 7.62mm NATO and .308 Winchester commercial ammunition in rifles built for either "caliber". (quotes intentionally used.)
 
2. It is possible to intentionally create a bad to dangerous load in either caliber, but why would you other than to prove a point erroniously by damaging a perfectly good firearm & possibly injuring a fellow shoter, just to make an essentially pointless point.
 
OK, having gotten that out of the way.
 
Some rifles are not designed for some loads, even in the (nominally) correct caliber. As an example I offer the Garand (a perfectly good rifle) being loaded with heavy bullets & slow burning powders. Yes you could mess up a Garand, but why would you, just to proove a point? The Garand was designed for a particular function, & it does that well. Can It be messed up? Heck yes, so can you think of a reason why you'd actually do this? I thought not.
 
There is a very good discussion on the .308/ 7.62mm non-issue right here on this forum, I respectfully suggest you actually read that thread first before bringuing this unicorn jousting non-issue up here as a seperate item.
After all there is no suggestion that the Garand is incapable of digesting 30-06 ammunitioin, because bad 30-06 loads can be developed, so whyn is there this silly discussion on the 7.62mm Enfield conversions being incapable of digesting suitable ammunition as well?


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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: Shamu
Date Posted: December 05 2009 at 7:13am
"If it says 7.62 on the rifle use 7.62, if it says 308 use 308."
That would make perfect sense, except that one part of my rifle says 7.62mm & the other says 3.08 winchester!
Using the logic you suggest should I use both interchangably, or neither?Geek
Even worse!!
I reload:
Shouild I use .308 Winchester dies, or 7.62mm NATO diesStar


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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: Smokey
Date Posted: December 05 2009 at 8:56am
In all honesty, I would get a bunch of once-fired 7.62mm Military brass, and reload it  using either .308 Winchester or 7.62mm dies. I would NOT try to duplicate the ballistics of either load though. LOL


Posted By: LE Owner
Date Posted: December 05 2009 at 9:56am
Originally posted by Shamu Shamu wrote:

Some rifles are not designed for some loads, even in the (nominally) correct caliber. As an example I offer the Garand (a perfectly good rifle) being loaded with heavy bullets & slow burning powders. Yes you could mess up a Garand, but why would you, just to proove a point? The Garand was designed for a particular function, & it does that well. Can It be messed up? Heck yes, so can you think of a reason why you'd actually do this? I thought not.
 
Quote After all there is no suggestion that the Garand is incapable of digesting 30-06 ammunitioin, because bad 30-06 loads can be developed, so whyn is there this silly discussion on the 7.62mm Enfield conversions being incapable of digesting suitable ammunition as well?
The problem some loads can cause when used with the Garand is not as good an example as the problems caused by heavy loads used with the 1895 Winchester, because the garand bolt and receiver isn't overstressed by those slow powder and heavy bullet combinations, the damage comes from high gas port pressure damaging the Op Rod, though I suppose an early opening of the action might result but with the gas port so close to the muzzle I don't see how.
 
The problem, such as it is, is in determining which 7.62 or .308 loads are suitable to begin with, and how far the design safety margin has been stretched by conversion to a higher pressure cartridge.
 
The winchester 1895 lever action was proof tested by a method accepted by the British authorities and required no reproof after being imported to the UK. Yet when that rifle was subjected to more advanced loadings of the .30/06 cartridge its safety margin proved to be inadequate. The result being excessive wear and increased headspace.
In recent decades reproductions of the Winchester 1895 have been manufactured using the best available modern steels and manufacturing processes, and proofed by modern SAAMI standards, yet from everything I've found published on these rifles the likelyhood that maximum pressure loads will cause the same sort of problems remains, and only the milder factory loads or equivalent are recommended.
 
When the UK NRA Safety Warnings were printed in their journals in recent years they were only repeating safety warnings that had been given before many years earlier. For decades owners of the converted No.4 rifles had taken heed of those warnings and proper 144 gr ammo was apparently readily available, thus no problems to speak of. Unfortunately in recent years a few have made a point of trying to dismiss such warnings as "Urban Legend" or "internet myth".
Also it appears that supplies of quality 7.62 ammo aren't so easy to find at affordable prices, a problem that has affected owners of other 7.62 rifles as well, and led to safety warnings posted on the sites of manufacturers of these rifles.
 
I very seriously doubt that those who urge others to ignore safety warnings are quite so quick to ignore them when it comes to their own rifles.
Their logic, if it can be called that seems to work like this. Say a warning is posted that underinflated tires cause accidents, the vast majority of drivers will either check their tire pressure on a regular basis or before a long trip, especially professional drivers, and at the very least even the least observant will be likely to add air to a tire that looks a bit low. Then someone comes up with the idea that since no accidents involving under inflated tires have been reported lately then the whole thing about under inflated tires causing accidents must be an urban myth, so they urge others to ignore the condition of their tires. If enough people buy their claim then sooner or later a blown tire costs a life. If so then where is our tire pundit? Will he accept full responsibility for loss of life by those who took him at his word?
 
The subject of "internet myth" reminds me.
The supposed withdrawal of the NRA safety warning due to some threat of legal action.
I don't know whether the UK has any concept of "Frivolous Lawsuit", but the basis of any such suit would have to rest on proof that such a published warning had somehow caused harm. ust who would be harmed by a safety warning?
The No.4 rifle was manufactured by government facilities and to some extent by commercial gunmakers working under government contracts.
No No.4 rifle was ever manufactured from the ground up as a 7.62X51 and marketed as such. Any No.4 rifle in that chambering is either a conversion of the .303 rifle or built on a receiver manufactured to be used for a .303 rifle. Enfield can not be harmed by any supposed defamation of the no.4 rifles that might arise due to their product being used in a manner other than the one it was designed and manufactured for.
If on the otherhand a supposed authority were to go out on a limb and garantee that any and all 7.62 NATO regardless of place and time of manufacture, conditions of storage, and intended purpose, or .308 Winchester regardless of bullet weight and power level is suitable for use in any converted no.4 rifle regardless of its age and number of rounds fired, and an accident did result, they'd be up the creek.
 
Lifting the warning because a few shooters wish to try to gain an edge in long range competition , or make use of cheaper surplus ammo ,would be irresponsible.
 
BTW
If the posted warning is no longer on the bulletin board at Bisley that is not a sign that the warning has been rescinded, Posted warnings usually have a specified time limit to allow the public to see them and take heed. also bulletin boards in public places have always been subject to vandalism.
From what I hear the warning is still in place in the offices themselves.
When the next issure of the NRA journal comes out perhaps we'll hear more on the subject.
 
 
PS
Consider these similar situations.
The .38 Special S&W Model 37 Airweight, a type of pistol I once owned.
Unbeknown to myself the Model 37 I owned had the original issue lightweight alloy cylinder.
When using the same ammunition I had used for many years in my Colt officers model target the chambers of the Model 37 began to swell. The loads were not particularly hot, far below the levels of modern +P loads.
Fortunately I recognized that something wasn't right and relegated that snubbie to wad cutters only. Only apparent damage was that now half the chambers could handle the larger diameter .38 S&W cases. Had it been necessary I could probably have use the .380 British revolver cartridge in an emergency.
 
Had I known at the time I would not have parted with that little snubbie, I found out later on that the alloy cylinders had been a subject of a factory recall and most were replaced free of charge by S&W so unaltered originals have some collector value. The pistol with original cylinder weighed near 3 OZ less than the later production examples.
 
Long before +P .38 Special ammo came along, or at least that designation, there was the .38-44 revolver cartridge, dimensionally identical to the standard .38 Special cartridge and manufactured for use with the S&W Outdoorsman .38 revolver, a forerunner of the .357 Magnum.
Any .38 special cartridge would work fine in the Outdoorsman S&W, it was a heavy frame pistol with thick cylinder walls. Use of the .38-44 cartridge in some less robust revolvers chambered for the .38 Sp could damage or destroy the gun, often on the first shot. Others might hold up to a good many rounds but the frame would be compromised by the added stresses.
 
Then take the .32-20 revolvers, and some rifles chambered for that cartridge as well.
The revolvers could digest the original standard velocity lead bullet loads very nicely, but the .32-20 also came in a high velocity jacketed bullet load meant only for rifles, and not for all rifles for that matter. Use of the high velocity loads quickly stretched or broke the top strap of many fine old revolvers, while some not manufactured with its use in mind managed to handle it without problems.
 
Then theres the extra hot 9mm loads meant for use in Submachineguns during WW2.
The Finns found that supplies of 9mm browning ammo for the 1907 Brownings they had in inventory was scarce. They found to their suprise that while the standard velocity 9mm Parabellum could blow the slide off a 1907 the high velocity SMG loads did not overstress the action though muzzle blast was fierce. The trick was that due to the short barrel the slow powder used to give maximum velocity in the 8 to 10 inch barrels of sub guns did not burn completely before the bullet exited the muzzle so pressures did not exceed the limitations of the browning blowback action.
On the other hand should these SMG loads be used in the 8 inch barreled artillery Luger or similar long barreled 9mm pistols the pressures could damage even a high quality locked breech pistol.
 
A similar extra high velocity load was developed for the Berretta and Villar Perosa SMGs. These were in fact chambered for the 9mm Glisenti rather than the 9mm Parabellum, though the two cartridges are to all intents and purposes dimensionally interchangable.
The standard glisenti pistol cartridge has a power level about that of the 9mm Browning, possibly less.
I've fired these italian SMG loads in a Browning P-35, believing them to be 9mm P. The first indication that things were not as they seemed was the truncated cone bullet similar to the original pre WW1 Luger bullets. The next was that despite a good hammer fall the primers were thick and hard enough that it took three strikes to set them off, the primers being intended for the heavy open bolt operation. When these rounds went off the muzzle blast rivaled the .44 magnum and the bullet threw up a shovelful of dirt from the backstop, striking power was about that of the .357 Magnum, and recoil was in proportion.
Those same cartridges could easily be chambered in a blowback Glisenti pocket pistol, no doubt with disasterous results.
The standard 9mm Parabellum has also been known to blow the slide off a Glisenti pistol.
 
 
The point is that simply saying that the .308 and the 7.62X51 are the same cartridge is wrong on several counts, the Standard NATO Ball is not the same "Cartridge" as the M118 Long Range Ball for that matter. The chambers may be nearly or even exactly the same dimensionally, but dimensions do not define the complete cartridge, and external dimensions do not define the cartridge case beyond placing a limit on which chambers it will fit.
 
The .308 winchester "Palma Match" cartridge for example uses a special semi balloon head case to allow a heavy long range match bullet to be used while maintaing a slightly larger effective powder space to avoid excessive pressures. How well this sort of balloon head case would act if fired in an Indian 2A chamber , especially if that chamber was manufactured on the loose end of the spectrum and then subjected to many years of indifferent cleaning practices is impossible to say. Add to that chamber pressures on the high side of the SAAMI specs for the .308, already near 20% higher than the standard operating pressure of Indian 7.62 Ball.
 
At this point there are just far too many variables at work to blithly state that any and all .308 Win is suitable for any and every rifle with a 7.62X51 chamber.
 


Posted By: Tony
Date Posted: December 05 2009 at 8:45pm
I don't know whether the UK has any concept of "Frivolous Lawsuit"

 To my knowledge we do NOT have "Frivolous Lawsuit" here in the UK. (But that doesn't gtee it doesn't exist I'm NOT a lawyer) My guess is Radway Green may have had words with the NRA because Radway Green manufacture nearly all the Brit ammo and the management may have thought the comments by implication included their current 762 production. material 

-------------
Rottie (PitBulls dad.)


“If electricity comes from electrons, does morality come from morons

Born free taxed to death!!!



Posted By: LE Owner
Date Posted: December 06 2009 at 5:45am
Originally posted by Tony Tony wrote:

I don't know whether the UK has any concept of "Frivolous Lawsuit"

 To my knowledge we do NOT have "Frivolous Lawsuit" here in the UK. (But that doesn't gtee it doesn't exist I'm NOT a lawyer) My guess is Radway Green may have had words with the NRA because Radway Green manufacture nearly all the Brit ammo and the management may have thought the comments by implication included their current 762 production. material 
The Safety Warning is in large part based on tests run by Radway Green personel among others and with their full cooperation.
Quote
 

AN INVESTIGATION INTO THE EFFECTS OF TIGHT

THROAT AND BARREL DIMENSIONS ON MAXIMUM

CHAMBER PRESSURES FOR THE 308 WINCHESTER

CARTRIDGE

This investigation carried out by;

THE PRESSURE TRIALS CONSORTIUM

Chairman

Dr. Geoffrey Kolbe,

Border Barrels Ltd., Riccarton Farm, Newcastleton, Roxburghshire, TD9 0SN

Members

Mr. John Bloomfield,

National Rifle Association of Great Britain, Brookwood, Surrey, GU24 0PB

Mr. John Carmichael,

JHC Supplies, Silverthorne House, North Piddle, Worcs, WR7 4PR

Mr. Alan Gidman,

Royal Ordnance, Radway Green, Nr. Crewe, Cheshire, CW2 5PJ

Mr. Roger Hancox,

The Birmingham Gunbarrel Proof House, Banbury Street, Birmingham, B5 5RH

(sorry about the size)
Nothing about the warning disses Radway Green ammunition, which has a sterling reputation, what it does do is to warn that some rifles may not be suited to use some specific types of Radway Green and other ammunition which uses bullets that are in fact the most common size in use today by almost every manufacturer of .308 and 7.62 NATO ammunition.
Personally I figure the supposed threat of legal action is one of those internet rumours we hear so much about, based on hotair, emotional reaction, and a disturbing tendency by a few to over estimate the strength of the LE type actions.
I've noted a similar lack of diligence in choosing suitable ammunition for other types of milsurp rifles, in large part based on misunderstandings about the intention of using rifle caliber cartridges for the various LMGs. The LMG can use the standard Infantry cartridge, and most more modern main battle rifles have a wide enough margin of safety to allow limited use of powerful specialized cartridges intended for the LMG and GPMG, but use of some such ammo can put great stress on a Infantry rifle.
A case in point would be the German Heavy Ball AP rounds used with the MG34. The Germans allowed its use in the 98K but only on a very limited basis, one five round clip of the AP ammo was issued to each soldier and only to be used in an emergency situation, if pinned down by fire from an allied armored car. Use of more than a few such rounds would damage the rifle.
That particular load was removed from inventory around 1943, due to shortages of the Tungsten used to make its core.
I accidentally fired a few rounds of that ammo which can in a mixed box of 7.92 surplus ammo, I thought the rifle had exploded the blast was so intense.
I threw the rest of that box of ammo into a pond, had I known how rare it is I'd have kept it, but never used it in a rifle.
Many believe that no military would load ammo for the rifle caliber machineguns that could damage a rifle, sometimes that has been a consideration but not always, its not a hard and fast rule.
I have run across quotes from British authorities which spoke of some lots of Mk8Z ammunition that was loaded extra hot, by accident more likely that by design, which gave such flattened primers that they looked "painted on", the velocity over 2900 fps and pressure estimated to be 60,000 CUP, far higher than would be prudent for a cartridge to be used in a rifle.
There have been recent warnings of European .303 MG loads that can wreck No.4 rifles, at least those which show any wear, and the warning stated that these could spring the receiver of a no.1 rifle.
I recently was given 60 rounds of FN manufacture .303 ammo, which I had thought to be MkVII or equivalent. I pulled the bullet from one and found it to actually be a long range MG cartridge, with a bullet type I hadn't seen before.
Its a boat tail bullet, but far different from the drawings of the MkVIIIz bullet. The tapered base is very long and the open base looks tiny in comparasion. The taper is far more radical than that of any military or match boat tail bullet I've seen. These had come in small 32 round boxes which probably means they were intended for use with the BREN Gun or other .303 LMG. 
After my experiance with those Mauser MG loads I figure I'll just break these down for components.
 
If sectioning a bullet reveals a lead core I may work up a safe load using these just to see how well they shoot in my no.4, but I won't try these with the no.1.
 
PS
The subject of use of oversized bullets comes up often when discussing handloading for milsurps.
In some cases use of an oversize bullet can restore accuracy if a barrel is worn or as in the case of 7.65 Mausers rechambered to .30/06 the bore is good but was oversized to begin with, .311 bullets have been used to load .30 ammo for these conversions.
The main problem of an oversized bullet in the often generous throat of a common variety milsurp is less due to bullet to bore fit, but rather the fit of the neck of the loaded cartridge in the neck of the chamber.
Also there have been a few experiments using grossly oversized bullets, the results which are usually poorly researched if at all and often misquoted, leading some to believe that oversize bullets don't raise chamber pressure.
 
 
Last but not least, to return to the question of whether or not the .308 Winchester can be considered to be the same as the 7.62 NATO, implying full interchangability, take a look at the following loads which are considered safe for a rifle proofed by SAAMI standards for the .308.
Loads were found at the Hodgdon site.
 
155 GR. SIE HPBT  IMR  IMR 4895  .308"  2.775"  43.5  2664  45,100 PSI  47.5C  2897  58,200 PSI 
  
 
155 GR. SIE HPBT  IMR  IMR 3031  .308"  2.775"  39.5  2594  43,400 PSI  43.2C  2832  58,500 PSI 
 
168 GR. SIE HPBT  IMR  IMR 8208 XBR  .308"  2.800"  39.0  2493  49,000 PSI  43.3  2707  61,500 PSI 
 
 
 
 
175 GR. SIE HPBT  IMR  IMR 3031  .308"  2.800"  38.0  2427  42,000 PSI  41.3  2653  59,100 PSI 
 
 
190 GR. HDY BTSP  IMR  IMR 4064  .308"  2.740"  39.4  2365  47,800 PSI  43.7C  2569  59,100 PSI 
190 GR. HDY BTSP  IMR  IMR 8208 XBR  .308"  2.740"  36.0  2303  51,700 PSI  40.0  2459  59,800 PSI 
 
 
{I do not recommend any of those maximum pressure loads for any converted WW era rifle, and would hesitate to use them in any but the best quality .308 rifle in excellent condition.}
Loads of the maximum pressure range of the above are commonly used for long range match competition
The lowest pressure starting load of the last one on this short list exceeds the operating pressure of NATO Ball only slightly and is within that rounds max deviation limit, but the maximum pressure load using same powder and projectile exceeds the maximum deviation pressure of M80 Ball by close to 7,000 PSI.
 
Earlier NRA Warnings on use of converted No.4 rifles required that these rifles be reproofed to a standard of 20 Long tons by the base pressure method, this being one long ton higher than its original standard of 19 LT and 1.5 LT higher than the earlier standard for .303 chambered Enfields.
That warning does not seem to have taken into account the greatly increased pressure ranges of long range match and heavy bullet hunting loads of the commercial .308 Winchester cartridge.
 
Pressure figures for both US Military Ball and most Winchester brand .308 are often much lower than those posted above, this is mainly due to the use of heavily moderated Double Base propellants that has the quality of acheiving good velocity with the lighter bullets at a significantly lower pressure than some other commonly used propellants. Unfortunately when bullet weights go above 150 grains those same double base propellants begin to lose that low pressure edge.
Australia , Pakistan, and some other users of the NATO cartridge have switched to Single base powders only for rifle caliber ammunition. Literature on British 7.62 production is unclear as to whether double base powders are used for the 7.62 in recent years, but state that a "Neonite" single base propellant was used during earlier production.
 
I've found nothing which indicates that bullets of heavier than 175 grains have ever been used for 7.62 NATO ammunition intended for use in combat or sniper rifles.
The tendency in recent years is to use only 150-125 gr bullets for 7.62 combat rifles, other than the occasional use of matchgrade ammunition with the modified M-14 rifles used by designated marksmen.


Posted By: Shamu
Date Posted: December 07 2009 at 12:52am
"The problem, such as it is, is in determining which 7.62 or .308 loads are suitable to begin with, and how far the design safety margin has been stretched by conversion to a higher pressure cartridge."
I assume you're thinking of the conversion from .303 British to 7.62mm here?
As we both know there is not a significant pressure difference between the 7.62mm NATO spec round & the .308 Winchester commercial round!
There IS a difference in how different regulatory bodies measure the pressure, but not the pressure itself.
 
However, I think you're missing the point of my post entirely.
 
It's not a question of HOW you could, in detail make a deliberately unsuitable load to intentionally belabor a point, it's the fact that it is possible, if you extend the parameters far enough, to damage a firearm even if using what is nominally the "right" cartridge for that firearm.
 
Let me clarify a couple of other points you bring up, again, adding to what I said to show the remark in a distorted & poor light.
 
I do not & will not suggest ignoring well researched & valid safey rules. To imply that I might is foolish at best, dishonest at worst.
 
To specifically associate British, .303 chambered rifles with Indian 7.62mm rifles is a somewhat unfair comparison.
The Indian rifles had far more than a barrel swap doe to them when they were being converted (upgraded?) to 7.62mm ammunition. The ammunition they were being upgraded to was 7.62mm, but NOT 7.62mm NATO! Lets not forget that minor hole in the apples to apples argument you present.
 
I repeat, with added emphasis, where it will help clarify.
 
There is no functional difference between 7.62mm NATO ammunition & .308 Winchester commercial ammunition. This specifically exempts certain "variations" on both 7.62mm & .308 Winchester ammunition, such as specialty loads developed after the 7.62mm design was finalized. (I'm thinking specifically of "Managed Recoil" & Light Magnum" type loads here).  It further assumes the firearm in which the ammunition is to be fired is in good mechanical condition & designed to fire that ammunition as issued.
 
I do NOT suggest using non NATO spec 7.62mm ammunition in anything, because it's not made to spec & some of the loads created in the 3rd world are unsafe in anything, regardless of chambering & condition. I'm specifically thinking of some lots of Israieli made TZ headstamped ammo, some years of Venezualian ammo, & lots of Indian & Pakistani ammo made after the late 70's when quality control was abandoned.
This is bad ammo, not ammo of a technically differing caliber & to use such examples as typical of all ammo is biasing results in the extream.
 
Likewise quoting home converted rifles that have not gone thru the entire conversion process. The Indian made 7.62mm Enfields were re worked in many ways in addition to swapping the barrel & bolt head/extractor. Even then the quality of those rifles is suspect as they were built under the same quality standards as the ammo previously discussed which no-one in thier right mind will touch.
 
In short I still believe that using one specific example of a match that doersn't match, & jumping off from that into the broad stament that the calibers are not interchangable is in error.
 
 
Would I use full house 7.62 loads in a #1 Enfield converted to 7.62 from .303? Heck no! (But I wouldnt use the same rifle in .308 Winchester either.)Star
 
 


-------------
Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: LE Owner
Date Posted: December 07 2009 at 4:13am
Originally posted by Shamu Shamu wrote:

"The problem, such as it is, is in determining which 7.62 or .308 loads are suitable to begin with, and how far the design safety margin has been stretched by conversion to a higher pressure cartridge."
I assume you're thinking of the conversion from .303 British to 7.62mm here?
Those are the rifles subject to the UK NRA Safety Warning, which is the main thrust of my posts.
I mentioned the 2A more or less in passing.
Quote
As we both know there is not a significant pressure difference between the 7.62mm NATO spec round & the .308 Winchester commercial round!
There IS a difference in how different regulatory bodies measure the pressure, but not the pressure itself.
Theres a very significant difference between pressures at each end of the bullet weight and velocity spectrum for both cartridges.
The difference comes in when you get into pressure ranges of the long range match and special ball cartridges compared to the standardized NATO Infantry Ball Cartridges. This is where the NRA Warning became necessary.
A rifle action considered suitable for extended use of cartridges generating 50,000 PSI may not hold up nearly as well if subjected to the sort of Long Range Match loads that are commonly used by other more robust action types.
 
Quote
 
However, I think you're missing the point of my post entirely.
 
It's not a question of HOW you could, in detail make a deliberately unsuitable load to intentionally belabor a point, it's the fact that it is possible, if you extend the parameters far enough, to damage a firearm even if using what is nominally the "right" cartridge for that firearm.
 
Actually we are on the same page here, if you'd noticed I earlier said that as long as you take care in chosing suitable ammo theres no problem.
 
Quote
 
Let me clarify a couple of other points you bring up, again, adding to what I said to show the remark in a distorted & poor light.
 
I do not & will not suggest ignoring well researched & valid safey rules. To imply that I might is foolish at best, dishonest at worst.
Actually I have a tendency to not limit a post only to a direct reply to someone I quoted earlier in the post.
I'm not sure where my words might appear directed at yourself since for the most part we seem to be in agreement.
 
Quote
 
To specifically associate British, .303 chambered rifles with Indian 7.62mm rifles is a somewhat unfair comparison.
The Indian rifles had far more than a barrel swap doe to them when they were being converted (upgraded?) to 7.62mm ammunition. The ammunition they were being upgraded to was 7.62mm, but NOT 7.62mm NATO! Lets not forget that minor hole in the apples to apples argument you present.
I think I already pointed out that India was not a member of NATO, and that while their 7.62 Ball is loaded to the same standard as other standardized infantry ball its not because of any agreement that might bind other NATO users.
The Japanese also manufactured 7.62 rifles and the 7.61X51 ammo they manufactured for those rifles is in an entirely different bullet weight and velocity class. Their ammo used a 125 gr bullet at a reduced velocity and pressure. The idea being to allow the fairly heavy main battle rifle in use at the time to be used in the manner of a reduced recoil squad auto if need be, smaller statured troops and women soldiers could then control the rifle better in burst fire from a bipod or in walking fire like the BAR they'd learned to respect.
 
Quote
 
I repeat, with added emphasis, where it will help clarify.
 
There is no functional difference between 7.62mm NATO ammunition & .308 Winchester commercial ammunition. This specifically exempts certain "variations" on both 7.62mm & .308 Winchester ammunition, such as specialty loads developed after the 7.62mm design was finalized. (I'm thinking specifically of "Managed Recoil" & Light Magnum" type loads here).  It further assumes the firearm in which the ammunition is to be fired is in good mechanical condition & designed to fire that ammunition as issued.
 
I do NOT suggest using non NATO spec 7.62mm ammunition in anything, because it's not made to spec & some of the loads created in the 3rd world are unsafe in anything, regardless of chambering & condition. I'm specifically thinking of some lots of Israieli made TZ headstamped ammo, some years of Venezualian ammo, & lots of Indian & Pakistani ammo made after the late 70's when quality control was abandoned.
This is bad ammo, not ammo of a technically differing caliber & to use such examples as typical of all ammo is biasing results in the extream.
 
I've been addressing the NRA Warning and objections to it, most of my posts have had nothing at all to do with your own earlier comments on the subject.
Perhaps I should have made that more clear.
The controversy over the converted No.4 rifles arose due to the dwindling supplies of British surplus 7.62 ammo of the type Radway Green had developed during the time frame when the L42 and similar converted No.4 rifles first appeared.
The 155 gr Radway Green ammo had proven problematic when used with converted No.4 rifles when first used, accuracy was not up to standards due to harmonics of the LE receiver and attendent bedding problems.
The ammunition used at NRA UK sanctioned matches is often restricted to the ammo they obtain and sell to the shooters.
From information gleaned from UK shooters comments some of this ammo differs in some respects from the ammo they'd used before.
The NRA felt it was necessary to warn against use of those ammunition types if they did not suit the chambering a bore sizes of those rifles which they say were optimized for the earlier slightly smaller dia bullets.
 
Quote
Likewise quoting home converted rifles that have not gone thru the entire conversion process. The Indian made 7.62mm Enfields were re worked in many ways in addition to swapping the barrel & bolt head/extractor. Even then the quality of those rifles is suspect as they were built under the same quality standards as the ammo previously discussed which no-one in thier right mind will touch.
I don't remember mentioning home converted rifles
 The majority of the conversions were done either by government facilities or by qualified gunsmiths and reproofed either in Britian or Australia.
 
Quote
 
In short I still believe that using one specific example of a match that doersn't match, & jumping off from that into the broad stament that the calibers are not interchangable is in error.
 
 
Would I use full house 7.62 loads in a #1 Enfield converted to 7.62 from .303? Heck no! (But I wouldnt use the same rifle in .308 Winchester either.)Star
 
 
Depends on what you consider "interchangable". NATO for example has a specific set of requirements for the NATO Ball cartridge with codes in the headstamp to designate which lots of ammunition are in fact "interchangable" by NATO standards, few if any commercial .308 cartridges can meet those specific requirements.
A major reason for the standardized ball specification was the conversion of WW2 era and earlier bolt action rifles to use the 7.62X51 cartridge.
While most such rifles had been originally chambered for cartridges that met or exceeded the chamber pressures of the 7.62 NATO some had used ammunition of significantly lower pressures, so chamber pressures of the standard ball were limited to the 48,000 CUP-50,000 PSI range.
As near as I can tell the only limitation on commercial .308 chamber pressures is the SAAMI Maximum pressure of 62,000 PSI.
Passing a proof test does not garantee how well a rifle will hold up to extended use of maximum pressure rounds. All the low number Springfield 1903 rifles were either proofed or reproofed at 75,000 CUP but those which had suffered from overheated forging continued to fail as the years went by and repeated shock of thousands of rounds fired took their toll.
All the converted Spanish Mausers including those with 1893-95 actions were reproofed, the action itself has sufficient strength for the standardized ball but there have been incidents when ammunition generating over 60,000 PSI got mixed in with imported Spanish ammo. The 93-95 actions did not have sufficient margin of safety to handle those occasional excessive pressures, they might have when new but some had suffered metal fatigue.
 
I think we both agree that so long as one takes the time to look into the measured chamber pressure of a particular load, determine whether or not the throat has sufficient clearance for the bullet type, and recommendations of regulatory bodies are not ignored, then the majority of .308 loads using bulets of 150 gr or less could be used safely in converted rifles.
But I think we also agree that one must not assume that the dimensional similarity of the .308 to the 7.62X51 would automatically mean that WW2 era bolt action rifles converted for use with the NATO standard ball would be suited to those heavy bullet maximum pressure loads deemed safe for modern sporting or target rifles.
Just as the Gew88 is not suited to the maximum pressure loads of the 7.92X57S cartridges, and the Win 1895 is not suited to post WW1 172 gr loads or the most modern high intensity .30/06 cartridges.
The malfunctions of autoloading rifles when using some .308 or .30/06 commercial loads are a matter of powder burning time rather than maximum pressures. There are US Military Olin Ball powder .30/06 loads intended for use in recoil operated Browning machineguns which will also cause malfunctions with the Garand, not due to pressure but because the Garand gas system was optimized for use with single base propelants which gave a lower gas port pressure. A similar situation to the switch from IMR to Olin ball which caused excessive rate of fire and occasional early unlocking and case separation with the early M16 rifles. The Olin ball actually having a lower pressure at the same velocity.
 
 
Well in short , Is the 308 fully interchangable with the 7.62X51? Answer would have to be no.
Is there a limited range of interchangabilty between the 308 and 7.62? the answer would be yes.
Are all 7.62X51 NATO cartridges interchangable and suited to every rifle chambered for that round? Well since NATO themselves never thought so the answer is a very definite NO.
 
As for the NRA Safety Warning, its exactly that a "Warning" and those who ignore warnings or encourage others to do so based on misreading or failure to understand the published data and extensive scientific testing by those closely associated with the manufacture of the ammunition and rifles don't get my vote.
 
 
PS
I have not been directing my posts at you or any particular individual on this thread. Fact is I haven't paid a whole lot of attention to anything which any particular individual may have said other than such things as the rumoured "legal action" and the difference between malfunction due to gas port pressure compared to over stressing the lock up with excessive pressures.
 
There are a great many action types which operate perfectly for centuries so long as the ammunition used does not inpinge too far on the actions safety margin.
I'd not recommend using 9mm NATO STANAG ball in a WW1 era Luger either, or the hottest available 7X57 loads in the 1902 Reminton Rolling Block rifles chambered for that cartridge.


Posted By: rhodders
Date Posted: December 07 2009 at 4:48am
after all the above it would seem to me the best choice for those of us with converted 303 to 7.62 x 51 "actions" eg my No4 mk1* with the L42A1 barrel is to buy some good quality 308 brass and reload within the tolerance of the original 303 action.
 
Or am I totally wrong ????
 
Rhodders
 


Posted By: Shamu
Date Posted: December 07 2009 at 5:12am
Originally posted by rhodders rhodders wrote:

after all the above it would seem to me the best choice for those of us with converted 303 to 7.62 x 51 "actions" eg my No4 mk1* with the L42A1 barrel is to buy some good quality 308 brass and reload within the tolerance of the original 303 action.
 
Or am I totally wrong ????
 
Rhodders
 
I'd say that way you had the best of both worlds.Wink
There's no rule that you HAVE to create "Elmer Keith Commememerative Ubermagnum" loads.


-------------
Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: LE Owner
Date Posted: December 07 2009 at 7:03am
Originally posted by rhodders rhodders wrote:

after all the above it would seem to me the best choice for those of us with converted 303 to 7.62 x 51 "actions" eg my No4 mk1* with the L42A1 barrel is to buy some good quality 308 brass and reload within the tolerance of the original 303 action.
 
Or am I totally wrong ????
 
Rhodders
 
 Probably so at least for optimum life of the rifle, though a properly converted and reproofed No.4 should be safe enough if care is taken to use only ammo that meets the original NATO specifications.
I had not heard of the extra tightbores being a part of these conversions till the NRA issued their warning. I had heard of the early production FN FAL rifles having this sort of extra tight bore coupled with Enfield patern rifling to ensure extended useful bore life, a figure of from 30,000 to 50,000 rounds was given for those barrels.
 
I found this on a site that produces barrels for NRA Match use.
Quote
Now that the much-reviled military spec bullets are largely no longer in use, there is only a very limited need for the tighter bore and groove diameters of past years.     The excellent 154 to 155 grain match bullets by Sierra, Lapua, Hornady, Nosler and  BJD work just fine with standard .30 calibre barrel dimensions. Of course these    bullets work very well in tight barrels too but pressures may be higher and bore fouling may increase. Simply put...if you are using match bullets, don't use the tighter barrels. The only application for the tighter spec barrels may be with UK shooters who feel that the Radway Green military issue ammunition groups better out of tighter barrels.
Apparently the earlier 144 grain bullets were only competitively accurate if used with this sort of tight bore. Bullets that gave no pressure problems when used in .308-.3085 bores seem to react less well to those tighter bores, Accuracy may be slightly better but at the cost of increased chamber pressures.
 
I'd given alot of thought to having a .308 barrel turned for a No.4 action with the idea of having a handy No.5 clone that could digest NATO ammo or commercial .308. At the time quality .303 ammo was scarce, with most locally available milsurp .303 badly degraded.
There were a lot of otherwise very nice No.4 rifles around with totally trashed bores, Replacement barrels were limited to the loose two groove take off barrels (often pretty doggy as well) and no one was making .311 barrel blanks.
 
Complete 7.62 conversion kits came on the market, with new barrel and boltheads, some with the proper magazine as well. Looking into these I found that despite the apparent advantages of such a conversion programs to convert large stocks of these rifles had been curtailed. Also despite the successful use of Mausers converted to 7.62 by Israel in combat, not a single third world user of the No.4 rifle had made such a conversion, even if their own Infantry rifles were now in 7.62. Rather than take advantage of cheap or even free NATO ammo for converted No.4 rifles they continued production of the .303 SAA, and used the no.4 for training or issued it and its ammo as a substitute standard, which would complicate logistics.
The Indian 2A rifles seem to have worked out very well but then again there police and other government agencies continue to issue the .303 rifles and the 7.62 rifles aren't seen nearly as often if at all in photos of recent troubles there.
The .303 rifles besides their use by government agencies have also been given on a limited basis to civilians living in areas of high bandit activity.
One would have thought that if the 2A rifle was considered to be as good or better than the .303 rifles they'd have kept the 2A for use by police and government agencies and sold off the .303 rifles rather than the other way around.
 
 
Anyway if in the unlikely event I ever do decide to build a No.4 converted to use .308 or 7.62 NATO I'd  use a new turned .308 dia barrel and be very careful of the ammunition I put through it, and to avoid the possibility of an heir using the rifle with unsuitable ammo I'd have to stamp a plainly worded warning in big letters filled in with bright red paint on the lefthand recever wall and on any visible portion of the barrel. "NOT FOR USE WITH CARTRIDGES GENERATING OVER 50,000 PSI".
 
 
Actually with the variable condition of milsurp ammunitions of all types these days I use only my own handloads in all my rifles. I learned that early on when that German MG load nearly caused a change of underwear. I was using an Persian Mauser Carbine so the blast from the short barrel left after images and ringing in the ears despite my sionics ear plugs.
Loads like those are probably what gave the 8mm conversions of the Carcano a bad rep.


Posted By: LE Owner
Date Posted: December 07 2009 at 7:17am
Originally posted by Shamu Shamu wrote:

Originally posted by rhodders rhodders wrote:

after all the above it would seem to me the best choice for those of us with converted 303 to 7.62 x 51 "actions" eg my No4 mk1* with the L42A1 barrel is to buy some good quality 308 brass and reload within the tolerance of the original 303 action.
 
Or am I totally wrong ????
 
Rhodders
 
I'd say that way you had the best of both worlds.Wink
There's no rule that you HAVE to create "Elmer Keith Commememerative Ubermagnum" loads.
I belive we agree on that. My point being that when a shooter new to the sport looks at the claims of the .308 being exactly the same as the 7.62 NATO and having no further information to go by they could easily believe that any load listed as safe for a .308 rifle would be perfectly safe for a converted WW2 Bolt action.
The No.4 actions weren't the only such conversions, and some of the other conversion which held up fine earlier on have shown themselves to be not so good in the long run.
There are Chilean conversions of 7mm 1895 rifles that used the original barrels with a chamber insert and then rebored and rechambered to 7.62. I recently ran across a site showing one of these barrels sectioned. The solder or brazing, cant tell which, operation to hold the chamber insert in place had succumbed to gas cutting, leaving a visible gap that in effect left the barrel cut halfway through just in front of the throat.
Other conversions of these rifles from 7.65 appear to have used new purpose made .308 dia barrels, these should be adequate for the Standard Ball, since the 7.65 has about the same operating pressures,  but I'd be very leery of using Special Ball or equivalent .308 heavy bullet loads.


Posted By: Unauthorized
Date Posted: December 13 2009 at 5:03am
With the disappearance of .303 military ammo the 7.62mm conversions of the #4 rifles are the best of both worlds for the handloader. The existence of plentiful brass would permit the conservative handloader to shoot without a lot of concern for lost brass. The .303 version with the larger chambers using retail commercial brass are expensive to feed due to the short case life.


Posted By: Shamu
Date Posted: December 13 2009 at 5:31am
"would permit the conservative handloader to shoot without a lot of concern for lost brass"
 
Someday I'll have to show you "Dumb Enfield trick #2"Star
Thats the one where every fired case drops neatly into the palm of the right hand, ready to be slipped in a convenient pocket for "next time".Shocked


-------------
Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: bullseye0317
Date Posted: July 15 2010 at 11:33am
Ok what i want too know is what rounds can i shoot in both 7.62 and 308? I am going to get a 2A made in 308... Can i shoot nato? But mainly what rounds and grain limits in both rounds do i have?
    
     Thanks


Posted By: Shamu
Date Posted: July 15 2010 at 9:27pm
NATO should be no problem at all.
I try to keep bullet weights between 125 & 168 grains with commercial or hand loads. Not because of some fictional percieved "weakness", but because the rifling twist won't stabilize 110 or 220 grain bullets.

The thing to remember with this ( & all similar debates) is to think it through instead of just reacting. The factory making the ammunition ensures that at any bullet weight the charge weight & velocity is within a standard.

The only difference I've actually found in any practical terms is the different internal case volume means you need to work up loads for each type separately, usually a 1~ 1 1/2 grain difference for the same velocity & pressure, and a slight difference in the setting up of the dies for re-loading to match the chambers (usually less than 1/4 turn of the die body).


-------------
Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: Cookie Monster
Date Posted: July 15 2010 at 10:52pm
Do not shoot .308 Winchester in a rifle chambered for 7.62 NATO. it is NOT the same There is many posts on here showing the dangers. The reciever on the Nato rifle is NOT designed to handle the greater pressures of the Winchester round


Posted By: LE Owner
Date Posted: July 17 2010 at 10:41am
Originally posted by bullseye0317 bullseye0317 wrote:

Ok what i want too know is what rounds can i shoot in both 7.62 and 308? I am going to get a 2A made in 308... Can i shoot nato? But mainly what rounds and grain limits in both rounds do i have?
    
     Thanks
The Indian Ordnance Factory site gives the specifications for their M80 Ball as nearly identical to the US military specs for M80 ball. The average working pressure is 50,000 PSI.
Max Deviation pressure of US M80 ball is 53,000 psi. These pressures are only a few thousand psi higher than SAAMI specs for the .303 British.
 
Pressure levels for specialized rounds like the 7.62 long range ball and long range target .308 ammunition can approach the SAAMI maximum allowable pressures for .308 sporting ammunition, which is 62,000 psi.
 
Before doing any shooting you should have the headspace checked, if the headspace exceeds SAAMI limitations for the .308 cartridge then you'd be going against a basic safety reccomendation by using any .308 ammunition. The headspace limitations are there for good reasons, and commercial sporting ammunition is not required to be constructed to allow for the often oversized military chambers.
Military headspace specifications can run several thousandths looser than commercial SAAMI specs, but military spec cases are constructed with that in mind.
 
US sniper rifles built on commercial Remington bolt actions are built to handle the maximum SAAMI pressures of .308 , and to all intents and purposes these rifles are .308 rifles rather than 7.62 rifles. The actions are among the strongest ever made and the rifles are assembled with great care at considerable expense. The ammunition for use in these rifles is a cut above any infantry ball ammunition, and manufactured to strict tolerances.
 
2A rifles sold off as surplus run the gamit in wormanship and condition, some in nearly new condition and manufactured without any wartime pressure, while others were manufactured as quickly as possible to act as a stop gap weapon, then used and abused and sold off with little in the way of inspection.
 
I have read an email sent out by an arms dealer telling a customer why he would no longer sell 2A rifles. Every 2A his company had testfired developed excessive headspace after firing only a few rounds of a common comercial .308 ammo, and he personally knew of a 2A owner nearly being castrated when his 2A after firing several rounds of commercial .308 ammo blew out at the breech sending the magazine into his crotch at high velocity.
Another importer wrote that he had found that all the 2A rifles he had received had excessive headspace, and that he had luckily obtained a carton of new boltheads which he had fitted to these rifles to correct headspace before he sold any of them.
 
A member of another forum has told of finding that the only .308 ammunition his rifle would digest without deforming cases too badly for economical reloading was the "reduced recoil" Remington .308 cartridges. Those reduced recoil cartridges are loaded to a lower pressure and ballistics are about the same as the .30-30 Winchester.
 
Taking all that into account I would not recommend use of any cartridge that exceeds the 50,000 psi average pressure of M80 ball in a 2A rifle in good condition.
Unless you can find a reliable source of information on the exact pressure level of the ammunition available you can not be sure whether any particular ammunition, either commercial or milsurp, is suited to the milsurp 2A rifle.
 
I've been told by a New Zealand shooter that some modern long range ammunition has been prohibited for use in L42 rifles and other converted No.4 rifles, the Lapua .308 was one such cartridge mentioned.
The British NRA has prohibited use of converted No.4 rifles with their standard long range competition cartridge, which the NRA buys in bulk under contract and sells to competitors, unless the rifles are re-proofed to newer standards. Enfield manufacture rifles such as the Enforcer were built as .308/7.62 rifles using carefully selected actions and proofed to a higher standard, these are considered safe so long as the rifle is in good condition and has not been altered since originally proofed (such as being rebarreled or otherwise altered from its original form).
 
I would expect that the 2A rifle , like the .303 rifles, will obtain its best accuracy and performance by use of handloads taylored to the individual rifle.
If you are a careful handloader you should be able to monitor the pressure range of your ammunition with far more precision than mass produced sporting ammunition, and be more certain of its quality than milsurp 7.62 ammunition.
Dangerously degraded milsurp 7.62 NATO ammunition has become more and more common these days, with a far too high number of rifles of all types being damaged or destroyed.
Best to spend a few more cents per round than to risk damaging a fine rifle trying to save a few bucks.
 
Theres an old saying "only accurate rifles are interesting" . In my opinion using old bargin bin milsurp ammo reduces serious target practice to expensive plinking.  
 
I handload for every centerfire rifle I've owned for any length of time, and gotten far more enjoyment out of shooting than I could have if limited to over the counter milsurp or sporting ammunition.
 
By not pushing the limits you'll extend the accuracy life of your rifle.
By using only ammunition in the pressure range the rifle was intended for while in service that rifle should remain servicable for generations to come.
 
PS
The NRA UK safety warning from their Spring 2010 journal
Quote

SAFETY NOTICE

ENFIELD NO 4 RIFLE CONVERSIONS TO 7.62MM

A safety warning concerning the use of Enfield No 4 Rifle actions converted to 7.62mm

was published in the Summer Journal.

After further consideration of all factors influencing safety of these conversions and

consultation with the Birmingham Proof Master, the following advice must be adhered

to in respect of the use of Enfield No 4 conversions:

• Owners of Enfield No 4 actioned rifles converted to 7.62mm currently

proofed to 19 tons per square inch are strongly advised to have them reproofed

to the current CIP standard (requiring a minimum mean proof

pressure of 5190 bar) which allows the use of CIP approved ammunition

with a Maximum Average Working Pressure (MAWP) of 4150 Bar.

• Conversions retaining their original Enfield barrel or a replacement barrel

as manufactured by RSAF Enfield are safe to use with commercial CIP

approved ammunition, which complies with a MAWP of 4150 bar, loaded

with any weight of bullet, providing they carry a valid proof mark, and

are still in the same condition as when submitted for proof.

• Conversions fitted with any other make of barrel (such as Ferlach, Maddco,

Krieger etc) should be checked by a competent gunsmith to determine the

throat diameter of the chamber/barrel fi tted before further use.

• Conversions where the throat diameter is less than the CIP specification

of 0.311” but not smaller than 0.3085” must not be used with ammunition

which exceeds 3650 Bar MAWP when fired in a SAAMI/CIP pressure

barrel.

• Conversions which have been checked and found to comply with Rule 150

may safely be used with any ammunition supplied by the NRA including

the 155 grain Radway Green Cartridge, 155 grain RUAG Cartridge or other

commercial CIP Approved cartridges loaded with bullets of any weight

provided that the ammunition pressure does not exceed 3650 Bar when

measured in a CIP standard pressure barrel.

• Owners of Enfield No 4 actioned rifles converted to 7.62mm who are

uncertain as to the proof status of the rifle should have it checked by a

competent gunsmith.

• Owners of Enfield No 4 actioned rifles in any calibre are strongly advised

not to use them in wet weather or without removing all traces of oil from

action and chamber prior to shooting.

• Enfield No 4 rifles converted to 7.62mm calibre or any other 7.62mm calibre

rifl es which are fitted with a barrel which has a throat diameter less than

0.3085” must not be used on Bisley Ranges.

• Ammunition loaded with bullets of any weight which are of greater diameter

than the throat diameter of the barrel must not under any circumstances

be used on Bisley Ranges in any rifle or barrel of any manufacture.



Posted By: DRC
Date Posted: July 17 2010 at 7:33pm
I got caught by this NRA warning, but luckily the gun dealer panicked and had the rifle re-proofed to 20T.  I then contacted the NRA and asked if I was welcome with my L42A1(?) and they said yes just bring the proof certificate with you.
 
As for the Lapua .308 ammunition, I was given a few boxes of it when I bought the rifle (Don't get too excited, it was VERY OLD).  Every round I shot (I didn't shoot many), the cases were difficult to extract and everyone showed signs of splitting.  All had the same shaped slit on the side near the base, like a small anchor shape about 3mm long.  I pulled the rest and found the powder to be a solid block and the inside of the case and bullet base to be very corroded.  Anyone want some cheap brass? Big smile


Posted By: LE Owner
Date Posted: July 17 2010 at 11:40pm
Well if proofed to 20LT the rifle is approved for ammunition with a maximum average working pressure of 4150 BAR which converts to 60,187.45 PSI. Call it 60,000 PSI.
 
If still carrying only the 19LT proof marking the rifle is approved for use with ammo generating no more tha 3650 BAR which equals 52935.95 PSI. Call it 53,000 PSI since SAAMI rounds to the nearest thousand.
53,000 PSI is equal to the Max Deviation numbers for M80 ball.
 
Many long range and heavy bullet loads for the .308 exceed 53,000 PSI maximum average working pressure by quite a bit, in the neighborhood of 57-59 K psi.
 
SAAMI maximum pressure for the .308 is given as 62,000 PSI. This doesn't mean that manufacturers normally load their .308 ammunition to 62,000 PSI, it means that when tested by lots the ammunition will pass so long as it does not exceed 62,000 PSI.
So while you may buy .308 ammunition from a particular manufacturer and test it with a pressure level of 57,000 PSI being normal for ammunition from that lot, you might later buy a box of identical ammunition from a different lot and some or all the cartridges from that box can generate 62,000 psi without the manufacturer being liable to recall the ammunition or pay for any damages it might cause to your rifle.
 
I've found no PSI equivalent for the pressures of the M118 Long Range 7.62 cartridge, its working pressure in Copper Units of Pressure is given as 52,000 CUP with its Maximum Std Deviation within lots given as 57,000 CUP.
 
There is no formula by which one can accurately convert a CUP pressure reading to a PSI reading.
In general CUP pressures of cartridges in the class of the .308/7.62 are far lower than the PSI pressures as tested by EPVAT transducers.
 
The addendum to the US Military's list of ammunition specifications gives the pressure of M80 Ball in both CUP and PSI the ammunition tested by either or both methods.
The Maximum Standard Working Pressure of M80 Bal in Copper Units of Pressure is 48,000 CUP, not much higher than the Working Pressure of MkVII .303 ammunition as tested by radial crusher at 45,400 CUP (SAAMI specs round this down to 45,000 CUP), and about the same as the maximum allowable pressures of MkVIIIz ammunition (though the later can be found loaded to the same pressures as MkVII depending on manufacturer and whether or not wartime manufacture resulted in increased pressures).
 
So converting or manufacturing a Enfield Rifle to handle standard M80 Ball is no great feat, if the rifles held up to firing MkVIIIz they should hold up to firing M80 Ball or its equivalent, but should be proofed to 19 LT at minimum even for the lower pressure Infantry Ball.
 
I'm fairly sure that M118 Long Range and Special Ball would push the limitations of rifles proofed to 20 LT, and if very many rounds that reached the maximum allowable deviation of 57,000 CUP were used these might cause irreparable damage to the rifle in the long run.
 
I've read that when converted No.4 rifles were proofed some rifles appeared to have passed proof but developed stiff bolts and difficulty in extraction. According to that source these rifles were condemned without attempts to rectify the problems.
Near as I can figure these rifles had suffered warpage of both bolt body and action body.
 
A member of another forum posted that a friends converted No.4 had suffered this sort of warpage when he'd fired the rifle with wet ammunition when it rained while they were at the range.
One of Martin pegler's books on sniping recounts a similar failure of a L42 rifle during the Falklands Campaign. The sniper reported that when in battle during a cold dizzle his rifle first began to lose its zero then the action became progressively more difficult to operate. He had to discard his L42 and continue the fight using a captured Argentine FAL rifle. Probably the scoped FAL the Argentines used as sniper rifles at that time.
 
Firing with wetted cartridge cases can increase bolt thrust, the higher the working pressure of the cartridge the greater this excess bolt thrust will be.
James Sweet's book on target range use of the Enfields tells of SMLE rifles suffering cracked action bodies if fired in the rain, in "extreme cases" as he put it. At the very least the SMLE rifle printed its groups far higher when ammunition got wet.
The No.4 also threw its groups high if ammo got wet, but theres no indication that the action body might crack, these being .303 chambered rifles not 7.62/.308 chambered conversions.
The P-14 .303 rifles threw groups a little higher but no where near as high as the rear locking rifles.


Posted By: bullseye0317
Date Posted: July 18 2010 at 6:30am
Is the Indian 308 ishy made out of a better metal so that it can shot the higher pressure ammo? In an ishy 308 could you shoot civilian 308 ammo in it? and 7.62? if so how high of grain in your 308 round can you get up to?
 
Just wondering because i am geting one.


Posted By: Cookie Monster
Date Posted: July 18 2010 at 6:52am
Originally posted by bullseye0317 bullseye0317 wrote:

Is the Indian 308 ishy made out of a better metal so that it can shot the higher pressure ammo? In an ishy 308 could you shoot civilian 308 ammo in it? and 7.62? if so how high of grain in your 308 round can you get up to?
 
Just wondering because i am geting one.
 
They are designed to shoot 7.62 NATO only. The receivers was upgraded from  .303 British to shoot 7.62 NATO.


Posted By: bullseye0317
Date Posted: July 18 2010 at 7:57am
really? dang. I saw somewhere that they made them out of a better metal so they could shoot 308 win. I really want to e able to shoot 308 win through it...would there be a way?


Posted By: bullseye0317
Date Posted: July 18 2010 at 8:10am

All the gun places and sellers a 308 win(7.62 NATI) by the ammo type it take too.



Posted By: Cookie Monster
Date Posted: July 18 2010 at 8:44am
Bullseye they are not the same  thus they are NOT interchangable !!
 
 


Posted By: Cookie Monster
Date Posted: July 18 2010 at 8:49am
Originally posted by bullseye0317 bullseye0317 wrote:

All the gun places and sellers a 308 win(7.62 NATI) by the ammo type it take too.

 
Of course they are telling you that, they want to sell you ammo. Please heed our warnings they are not the same


Posted By: John Coleman
Date Posted: July 18 2010 at 9:13am
In 1984, American Rifleman Magazine listed some pressure testing that had been done in a 24 inch Remington "test barrel". I'm guessing a commercial test barrel would have a tight, minimum SAAMI chamber. Groove diameter .308", rifled four grooves .176" wide, right-hand twist, one turn in 12 inches. Here are a few military loads they tested. Velocities were measured 15 feet from the muzzle.

WRA-68 148 grain M80 ball - 2829 fps - 48,700 CUP

LC-81 168 grain M852 - 2676 fps - 53,900 CUP

LC-77 174 grain M118 - 2650 fps - 55,400 CUP











Posted By: A square 10
Date Posted: July 18 2010 at 9:49am
thanks for opening it back up - there is always a wealth of information [new and old] that come from these 'discussions' , they never get settled - they never get resolved , its been going on for years everywhere on the net , we each must read 'all' of the data presented and decide for ourselves , thats why i dont enter the fray but do read with delight the new info that gets presented and weigh it carefully , this is a very interesting topic and i always enjoy the debates 


Posted By: LE Owner
Date Posted: July 18 2010 at 10:40am
Originally posted by bullseye0317 bullseye0317 wrote:

really? dang. I saw somewhere that they made them out of a better metal so they could shoot 308 win. I really want to e able to shoot 308 win through it...would there be a way?
Before 1965 , starting around 1950, Indian .303 SMLE rifles were made from an alloy steel called SWES48. I have no idea what this steel contained but after awhile they found that it gave an unacceptably high percentage of failures of action bodies during the normal run of proof testing, which at the time consisted of one dry proof cartridge and one proof cartridge that had been oiled, the oiled cartridge putting the maximum back thrust on the bolt as the final proof test.
 
They found they needed rifles and for whatever reasons they chose to stick with SWES Steel and suspended use of the oiled proof test cartridge to reduce the number of failed actions.
Around 1965, perhaps a bit earlier, the Ordnance factory obtained a better alloy steel, described as an EN steel, EN is a European grading system EN standing for European Normal.
I've read from numerous sources that the EN steel contains Vanadium. I looked up the use of Vanadium in Steel and found it was introduced in the Automotive Industry to produce high strength axles, and such alloys are very resistent to deformation from repeated shocks, such as the stresses on an action due to firing of high powered rifle cartridges.
 
The EN steel is definitely better than the SWES48 steel, but how strong it actually is I can't say without knowing its exact number to compare to the European Union list of EN alloys.
 
Its common for gunmakers steels to be found in the listings of alloys used by the automotive industry. Most US gun alloys have a SAE number, which can be used to discover its alloying metals and general properties.
 
British manufacture SMLE rifles used alloys listed by a system unique to Britian at that time. It took awhile but I finally ran down the specifications for the steel used by Britian, a medium high Nickel content steel, also known for resistence to shock and ability to recover from stretching under pressure. That steel is similar to the steel used to make the M1917 and P-14 rifles, but with a lower nickel content on average. The highest nickel content of steel used for the SMLE is within the range of that used for the M1917, but the lowest acceptable Ni content of steel used for the SMLE is about one percent less than that used for the M1917 rifles. 
This means that some SMLE rifles are far stronger than others.
 
I suspect that Indian .303 SMLE rifles manufactured before 1950 are a good deal stronger and more reliable than many .303 SMLE rifles manufactured between 1950 and 1965 when 2A rifle production began.
 
If you insist on using .308 ammunition you should first have the headspace checked and if its not within SAAMI limits for .308 you might as well forget it.
If by some chance headspace is within limits for the .308, find out which brands and loadings of .308 generate pressures no higher than 48,000 CUP- 51,000 PSI, the same pressure range as M80 Ball.
The Managed Recoil .308 by Remington has been recommended by 2A owners
http://www.midwayusa.com/viewproduct/?productnumber=233209 - http://www.midwayusa.com/viewproduct/?productnumber=233209
 
Federal also makes a Low Recoil reduced power .308 load, that may be suitable.
 
As always any such ammunition should be used only in rifles that are in safe shooting condition, meaning a good bore , good chamber, and headspace within SAAMI specifications.
 
Better all around if you use only military 7.62 NATO cases and assemble handloads using the bullet types you would wish to use with .308 sporting or target ammunition.
The milspec casings are better able to compensate for generous milspec headspace and loose chambers.
 
Otherwise I would not recommend the 2A rifle.
The .303 rifles are as powerful as you are likely to need a rifle of this type to be, and both sporting and milspec .303 ammunition is available at reasonable prices.


Posted By: bullseye0317
Date Posted: July 18 2010 at 2:54pm
Alright, I will cheack the headspace. What If mine wasmade in 1966? That would be the best of he bst steel right? In the indian 308.


Posted By: LE Owner
Date Posted: July 18 2010 at 11:08pm
Originally posted by bullseye0317 bullseye0317 wrote:

Alright, I will cheack the headspace. What If mine wasmade in 1966? That would be the best of he bst steel right? In the indian 308.
Probably so, since they had only recently begun production, so they'd probably have taken extra care with the first examples.
Then again condition is very important. An older rifle might have seen far more use and perhaps have been rebarreled later on. But age is not a definite clue to condition. Some early production rifles may not have seen as much use and abuse as many later production rifles.
 
There have been reports of 2A rifles built on the older SMLE action bodies, but I have my doubts about some of the claims made about these rifles over the years.
One never knows what sort of mix and match franken rifles can pop up when huge numbers of obsolete rifles hit the surplus markets.
 
Probably the best bet would be to buy from an owner who'd had the rifle in his possession for some time and fired it enough to have discovered any flaws long before deciding to sell.
 
When a major changeover in production takes place anomolies can pop up. When Springfield production switched over to the double heat treatment methods to cure the problem of brittle receivers an unknown number of older receivers in unfinished condition somehow got folded into the production lines. A few receivers that should have been of the high number metalurgy were found to be identical to the suspect low number receivers, and there were failures of these that had ordnance officers scratching their head for awhile.
 
The reports of 2A rifles built on receivers carrying markings no longer in use in the 1960's on might have been the result of such a snafu at the factory.
Since .303 rifles remained in use, its also possible that a few sent to the factory to be refurbished got mixed in with 2A rifles and were rebbareled using 2A barrels by mistake.
 
As for the SWES48 alloy I suspect that those which did pass the standard oiled cartridge proof would be plenty strong. Sometimes strength of the alloy itself is not the problem. If switching to a new alloy heat treatment methods formerly used in SMLE production may not have been suited to the new alloy. This could have resulted in many receivers not being up to snuff.
 
The EN alloy is probably not only stronger, but less sensitive to variations in temperatures during the heat treatment process.
I also suspect that the maching qualities of vanadium steel would aid in preventing crack propogation at critical points.
The main area of crack formation of the SMLE action body appears to be at the rivet holes where the charger bridge is mounted. They use a shrink riveting method there, and this might act to widen any flaws in the steel over time.
Loosening of the charger bridge was a sign something was going south with that action body, and could result in a rifle being condemned or set aside for Drill Purpose only.
Owners of the earlier LE rifles feel that the lack of a charger bridge and its mounting holes makes those action bodies stronger than the later SMLE action bodies.
Near as I can tell most Lee Enfield actioned sporting rifles from major manufacturers used the older style action body without charger bridge.
 
Simply altering the machining process at the charger guide mounting could improve the strength of the action. The newer alloy would also improve overall strength and durability.
 
With this type of action durability over the long haul is as important as estimates of ultimate strength derived from proof testing.
 
I'm reminded of the brand new 1953 Mercury my father once bought. The front axles were obviously strong enough when manufactured but only two years later the right front axle snapped off due to metal fatigue, though the car had never been subjected to any abnormal stesses.
Luckily no one was injured.


Posted By: bullseye0317
Date Posted: July 19 2010 at 8:30am
Ok that was alot of help. How would I tell by looking at the gun if it is made out of the good steel? And if it is could I shoot all of the 308 win ammo? What ones could i shoot with it?


Posted By: LE Owner
Date Posted: July 19 2010 at 2:09pm
Originally posted by bullseye0317 bullseye0317 wrote:

Ok that was alot of help. How would I tell by looking at the gun if it is made out of the good steel? And if it is could I shoot all of the 308 win ammo? What ones could i shoot with it?
Well other than the date of manufacture, if well into the post 1965 production of the 2A, I don't think just looking at the rifle can tell you much about its metalurgy.
 
If the rifle shows honest wear, signs that it has fired more than just a few rounds of Indian issue 7.62X51 (India was not a NATO member state but adopted the NATO cartridge) and shows no signs of set back of locking lugs or recesses and still has good headspace , then its very likely that the metalurgy is as good as they get.
By this I mean that the rifle has proven to be durable in normal conditions, which actually tells you more than its proof tests would if the rifle had been unissued and never fired since being proof tested.
Numbered parts should all match, bolts don't interchange between rifles, though a non matching bolt from another rifle can be fitted well enough to work okay. Unfortunately a retrofitted non matching bolt is likely to result in increased headspace.
 
I've fitted a new unissued bolt to my 1915 rifle, not rocket science but it does require a fair amount of skill.
Bolts were hand stoned to insure reasonably equal bearing of the lugs, and the Proof testing rounds completed the mating of locking syrfaces by driving them together under high pressure, insuring full mating of these surfaces, which is necessary for best accuracy and safety of the lock up.
 
If a guide rib of the bolt body shows upsetting of the metal at the rear, this can be a sign of either soft steel, or that the rifle has been subjected to excessive pressures.
There should be no stiffness or drag when moving the bolt forwards and backwards, and no excessive side play of the bolt.
Enfield have a reputation for loose tolerances to allow them to continue to operate when dirty, so some play is expected, but if theres a lot of side play it may indicate that the rear receiver walls have spread. 
 
The bolt head should clock in without excessive overturn. When screwed in the extractor lug of the bolt head should line up with the guide rib. A slight overturn is allowable, but more than ten degrees overturn is reason for concern. In wartime as much as twenty degrees might be allowable for a well worn .303 SMLE, but thats pushing things into the danger zone. I don't know how much overturn they'd allow for the 2A, but any overturn is a sign of wear, or a mis matched replacement bolt head.
 
So far every Indian manufacture .303 SMLE I've cleaned and examined showed signs of the extractor having been stoned at some point, in an effort to improve its function I suppose. Some were very worn down, and may have been stoned due to a chipped blade or some other problem when a replacement was not available. They all worked though. 
One possibility would be that ammunition that had a relief cut above the rim had been used at some point. I found that a new unaltered extractor sometimes hangs up in the relief cut causing failures to eject still the edge of the blade was stoned to thin it, the unaltered extractor not being able to push the case to the left as it does normally.
Winchester and HXP .303 have this relief cut, other milspec .303 does not have this cut so far as I can tell.
 
I have run across a few .303 Indian rifles that showed some setback and/or upsetting of metal at the guiderib, loose or even cocked at an angle bolt heads, and one that had nearly invisible ripples in the bolt body.
I'd assumed that these had been damaged by use of MkVIIIz machinegun ammunition, or tropical heat degraded ammunition that had generated excessive pressures, but thats was before I learned of the problems with pre 1965 SWES48 steel action bodies.
 
India was long involved in genocidal warfare with Pakistan, and every rifle that could shoot was fielded , some that probably should have been retired decades earlier.
Ammunition supply seems to be a bit iffy as well, with police stations still keeping 1960's and earlier MkVII ammunition in stock for their .303 rifles. This resulted in many misfires and poor shooting by police at Mumbai during the terrorist attack there.
 
Very few of the 2A rifles ever showed up in stores here, but many of the wire wrapped Indian grenade launcher rifles were sold here.
These looked to be a good buy. They had been either refurbed or manufactured new for use as grenade launchers. Stocks appeared new without a ding and no oil stains, metal finish was perfect.
Apparently India had huge stocks of .303 grenade launching blanks on hand, so rather than make or buy 7.62 grenade launching blanks ,( available 7.62 blanks may not have been suitable for a cup discharger since most NATO rifle grenades are the shoot through type that can be lauched with live rounds) ,they decided it was better to issue available .303 rifles for this purpose, and spare the 2A rifles from the wear and tear associated with grenade launching.
Usually the British only chose rifles that for one reason or another were considered suitable for live ammo only in emergencies, and stamped "EY".
All the Indian GL rifles I've seen looked to be in perfect shape, not recycled clunkers. They also looked to have been placed in storage and never issued.
 
 
Well thats a bit long winded but I'm enjoying the discussion.
 
I hope you find a good 2A rifle, I know there are many good ones out there.
 
 
PS
 I can't really be sure, but it seems to me that winchester may have managed to keep the pressure levels of its 150 gr .308 ammunition very close to the original specs. They liked to used Olin double base powders which have a rep for good performance at lower pressures than most other powders.
One reason that double base ball powder was chosen for most 7.62 production was that it gave a bit lower pressure in the shorter NATO 51mm case than IMR powders once used with the .30-06.
Australian 7.62 NATO and some others use single base powders only, since these were better suited to the FN FAL gas system, and less erosive to bores and pistons than DB powders.
 
I've been very leery of milsurp 7.62 ammo since a batch of FNM ammo began to self destruct on me.
I pulled the bullets and tried to salvage the powder, but it ate through a steel powder canister and released an corosive vapor that rusted up every steel object near the canister.


Posted By: John Coleman
Date Posted: July 21 2010 at 7:32am
Originally posted by LE Owner LE Owner wrote:

[QUOTE=bullseye0317]
 I can't really be sure, but it seems to me that winchester may have managed to keep the pressure levels of its 150 gr .308 ammunition very close to the original specs. They liked to used Olin double base powders which have a rep for good performance at lower pressures than most other powders.
One reason that double base ball powder was chosen for most 7.62 production was that it gave a bit lower pressure in the shorter NATO 51mm case than IMR powders once used with the .30-06.
Australian 7.62 NATO and some others use single base powders only, since these were better suited to the FN FAL gas system, and less erosive to bores and pistons than DB powders.
 
I've been very leery of milsurp 7.62 ammo since a batch of FNM ammo began to self destruct on me.
I pulled the bullets and tried to salvage the powder, but it ate through a steel powder canister and released an corosive vapor that rusted up every steel object near the canister.


As I remember a few stories about developing 7.62x51 and 308 Winchester, Winchester was kind of left behind when the US military decided to use IMR powders for the service rifle cartridge. IMR-4895 had been developed for use un 30-06 by Dupont in 1941. In 1944 it was decided to use only IMR-4895 in all 30-06 ammunition. Well Dupont did have some political and military connections but so did Winchester. During WWII Winchester loaded 303 for the British using Ball-C powder.

After the war the US Army had seen how modern and advanced the German small arms were. The US Army wanted to develop new, more modern weapons. Well the US had won the war and was downsizing the military. Congress wasn't interested in spending any money on new weapons.

Well a couple of things happened. One was the Cold War. Congress realized the communist countries were developing new arms. Another was Winchester wanted to be the US Army rifle ammunition maker.  Winchester demonstrated that it could get near 30-06 velocity from 300 Savage using their ball powder. The US Army wanting an angle to get Congress to spend money on new arms thought this might be a good way to do it. Also Winchester still had some connections.

The US Army wanted the cartridge to be better for automatic weapons than the sharp shoulder of 300 Savage and they wanted the velocity to match 30-06.  This caused the cartridge to increase in size a bit. The original bullet was steel core with no lead. The selling points to Congress was the "shorter" case used less copper than 30-06 and the bullets used no lead. Both were in short supply in WWII. In order to use this new cartridge the US Army of course needed new weapons. The US Army desired lead core bullets and the fact that M80 ammunition was originally "overhead live fire training" ammunition was an excuse to develop and make lead core ammunition.

Winchester thought  the development of the cartridge and use of ball powder would insure that Winchester got exclusive contract to make 7.62x51 for the US military. Well Dupont still had very strong connections. The ammunition contracts were originally split between Winchester and Remington which was owned by Dupont. Remington and Dupont got approval to use IMR-4895 powder and the increase in case capacity from 300 Savage was just enough to allow IMR-4895 to reach the rated velocity. Later Remington and Dupont switched from IMR-4895 to a short cut version of IMR-3031 called IMR-4475 for easier machine loading of cartridges. Had the original case capacity been the same as 300 Savage, double base ball powder might have been required. The velocity of 7.62 NATO is 2750 fps +/- 30 fps at 78 feet or 2809 fps +/- 30 fps at the muzzle (some sources say 2808 fps at the muzzle).

Winchester did get a contract for 30-06 M2 ammunition during the Korean War. It did use ball powder and the powder was position sensitive and caused 'ringing" of the rifle chambers, damaging the rifle. The powder was surplussed and sold by Hodgdon as H-380.


Posted By: bullseye0317
Date Posted: July 21 2010 at 7:52am
Ok, thanks ill just buy 150 grain 308 win and all 7.62 that loks in goot shape. When my gun comes in ill check it out and get back on how it checks out. The pics looked nice and made in 1967 or 1966. Looks like there is no black paint covering it and nice finish. But ill look and make sure everything is fine. I hope it is becuase I cant return it...Ill explain what i get and how it is too you (LE Owner) and you give me your advice. Thanks!

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