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Reloading Info for 174 gr Bullet

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Category: Reloading
Forum Name: Reloading .303 British
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Printed Date: October 26 2020 at 4:14pm
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Topic: Reloading Info for 174 gr Bullet
Posted By: gunner69
Subject: Reloading Info for 174 gr Bullet
Date Posted: May 09 2020 at 6:36pm
I will be reloading for a Jungle Carbine.  I have been given a sack of mixed brass once fired cases.  I plan on full length sizing these cases and loading 174 gr or 180 gr Soft Point Bullets.   Not sure what powder to use.   I will be using the Battle Sights with the ladder option.   Probable range will be under 100 yards.   

After the initial firing in my Jungle Carbine I will switch to a set of Lee Neck Size Only dies.  This should help keep the cases in good shape for multiple use, and prevent case seperation.

I read on a Canadian Forum that some people put an "O" Ring on their ammo to help head space the round?   Would it be of benefit for me to add an "O" Ring and if Yes what size "O" Ring.

I am thinking that my neck sizing only I won't need the "O" Ring idea.

P.S.  If you own a Jungle Carbine and have an accurate load for either the 174 or 180 grain bullet you are willing to share thanks much.


-------------
Jack Lalley



Replies:
Posted By: britrifles
Date Posted: May 10 2020 at 3:55am
An O-ring can help on the first firing after FL sizing to minimize stretching of the case web (sides of the case just forward of the case head).   The O-ring keeps the case head in contact with the bolt head.  This first firing should blow the shoulder forward so that subsequent loadings are headspaced on the shoulder.  

I’ve never tried O rings on the cases, none of my No. 4 rifles have large headspace.  I typically get 50 reloads on my brass, FL sizing about every 10 reloads just enough to bump the shoulder back a few thousandths. 




Posted By: Goosic
Date Posted: May 10 2020 at 7:41am
britrifles.  Can you explain in detail how you are managing 50 reloads out of your brass please? The barrel on my Long Branch is a New Old Stock item that was never installed and I specifically used brand new Canadian brass to look at case expansion and neck stretch, etc,etc. After reloading a total of 5 times. I ended up with 21 cases separating  out of 100. I then used 50 brand new Hornady cases.  After a total of five reloading sessions I ended up with 12 case separations out of 50 cases used. I purposely kept all the cases neck sized only for added measurement. I then took one 20 round box of once fired,full length resized Norma cases and went to work on those.  Full length resizing only after every firing. It was during the sixth firing session I had the beginnings of case separation on two cases and one case totally separated. I have tried the O ring trick, I have tried neck sizing only,and I have full length resized only. I cannot get more then 5-7 reloads without a case failure.  


Posted By: britrifles
Date Posted: May 10 2020 at 9:38am
Goosic, it might be the brass I’m using, mostly Canadian Mk 7 service cases which tend to be a bit heavier in construction than most commercial cases.  I’ve reloaded RP cases at least 15 times now with no case head cracking, but my routine loads are with military DI and DAC cases which last about 50 reloads.  

Headspace on my rifles are just over minimum (0.064) and the military case rims are 0.062 - 0.064).  Also, I tend not to load to, or near, maximum.  I believe these are the major factors along with using a neck sizing collet die. 

If you remove the extractor and insert a GO gage, you can get an idea how much over minimum headspace you have by pushing/pulling the bolt forward/aft.  The Long Branch Mk 1/2 I just refinished, there is no perceivable movement of the bolt when closed on the GO gage.  Without the gage in the chamber, the bolt should move fore/aft a bit.









Posted By: Goosic
Date Posted: May 10 2020 at 9:55am
Welcome from Phoenix Arizona gunner69.
If you do neck size,remember that you will need to full length resize at some point in time.  I can share with you my particular accurate handload as can every handloaded here. That being said however. Find a powder and primer that suits your needs, as well as the bullets. Graf and Sons does offer a .312 diameter 174grn BTHP that works exceptionally well in a worn Enfield barrel. Start with the minimum charge weight and seat the bullet as per the manual.  
Varget and IMR4064 powder has the same burn rate and is used for 174/180grn bullets. 150grn bullets fair well with IMR3031.  If your wallet has extra cash in it, Norma 202 powder has the same burn rate as the Varget and IMR4064 and as an added bonus was made specifically with the 308 Winchester round in mind.
(For reference purposes only)
My accuracy handload for the Enfield:
174grn .312 BTHP GRAF bullet
40.0grns Norma powder
WLRM primer 
OAL 3.050"


Posted By: Goosic
Date Posted: May 10 2020 at 10:20am
My Canadian cases are made to military specs as per their listing.  They have a uniform rim thickness that averages 0.0625" I use the minimum charge weight of 40.0grns of Norma powder as per the Norma manual.  I set aside X amount of brass for my LB and have neck sized only. I have no discernible issues with the cases after firing until about the fifth reload when I start getting separated cases. The following picture shows two cases from the same batch. The fired case in appearance looks no different then the reloaded case. These two cases are on their respective fifth reload. The loaded round is from a batch of fifty where I had nine separated cases. Headspace is not the issue here. I have used Winchester, Remington, Norma, Herters,PPU,and this new Canadian stuff. If I make it past seven reloads with all I have listed, I feel extremely fortunate. 


Posted By: gunner69
Date Posted: May 10 2020 at 11:15am
So what is your source of the Canadian .303 Brass?  Sounds like I can forget the "O" Ring idea, eh?  I have IMR 4064 and H4895 on hand.   Who shoots the No.5 Jungle Carbine here?

-------------
Jack Lalley


Posted By: britrifles
Date Posted: May 10 2020 at 4:10pm
Military brass doesn’t typically have the groove right above the rim. It also tends to be a bit thicker in the web area.  Brass composition may also be different.  The brass I am reloading is 1943 and 1944 Defence Industries (DI) brass.  Also 1956 Dominion Arsenal (DAC).  I had one box (48 rounds) of 1958 DA brass that lasted two reloads, they all cracked at web.  

I’m not aware of any Canadian made commercial .303 brass that was manufactured to the exact same specification as the Mk 7 Service ammunition.  

Might be an illusion, but the case on the left looks like the brass is strained about 1/2 inch above the head. 

You said headspace is not the issue, does that refer to your specific rifle, or do you think headspace plays no role in case head cracking?










Posted By: Goosic
Date Posted: May 10 2020 at 5:21pm
Headspace is not the causality of the case separations. The cases do not show any issues until I get approximately 5-7 reloads down the line. My Lake City 7.62x51 brass starts to separate after 7 reloading sessions. 
The line you are referring to is from the sizing die. It was not cleaned before I installed it and left that mark. The separation typically happens 3/8" above that line. I have no cause for concern here for I am confident everything I am doing reloading wise is safe. The added knowledge of knowing the condition of this barrel,headspacing, and the fact that the Enfield rifles were not designed with the intent for it to be reloaded for does not cause any alarms as well.
I am just genuinely impressed with the 50 reloads you achieve and wanted to know if you could be kind enough to give me/us a little insight as to the secret to your success...


Posted By: britrifles
Date Posted: May 10 2020 at 6:05pm
I think headspace has much to do with it.  I may be wrong, but it goes to reason that the less the brass has to stretch to contact the bolt head the better.  James Sweet, an avid LE target shooter, Queens Prize winner, author of “Competitive Rifle Shooting” advocated to maintain headspace to 0.064 to 0.067 and measuring cartridge case rims discarding those that are thin.  

If your rifle is headspaced at 0.064, then it must be something else.  Perhaps is is down to the brass I’m using.  I just recently started using PPU, at least 5 reloads on it so far.  

No reason to think you have anything wrong in your rifle or loads.  

No secrets at all, I explained why I think I’m able to get that many reloads.  Most of these were shot in my Long Branch No. 4 Mk 1/3 with BSA barrel.  It does have a long chamber (head to shoulder), but I don’t think that is a factor in case life.  

I don’t think I’ve had any case head cracking in my 1959, 1960 and 1962 Dominion Arsenal 7.62 NATO brass fired in my No.4 DCRA conversion.  I’m sure some of that brass had at least 25 reloads, and probably more.   I usually get about 30 reloads of .30-06 in my M1 reloads before the necks split.  

I keep all brass separated to each rifle, I do not FL size for bolt rifles, the chamber lengths in my four .303 No. 4 rifles are all different.  I only FL size when absolutely necessary, and even then, just bump the shoulder back a few thousands.  






Posted By: Goosic
Date Posted: May 10 2020 at 6:36pm
With a .064 go gauge installed and the extractor claw removed, I can get a .001" feeler gauge slipped between the bolt face and the gauge with slight resistance.  All my cases average out to 0.0625" plus or minus .0005". This is the Long Branch.  The faux No4MkI* T rifle is tighter with the five groove BSA N.O.S. barrel. I have separated my brass between the two,keeping specific brass to a specific rifle and regardless of rifle used my average reload until case separations occur is between 5 to 7,no more,no less...


Posted By: britrifles
Date Posted: May 10 2020 at 7:29pm
A mystery then, or just a difference in the brass?  Don’t know...will be interesting to see how many reloads I get from the PPU brass.  I started with new cases for my 1941 0L Long Branch Mk 1/2, I will track the actual number of reloads and let you know the results.  The range is opening back up and I’m itching to shoot this rifle.  


Posted By: Zed
Date Posted: May 11 2020 at 4:14am
Britrifles; if you were getting 15 reloads out of Remington brass; I would think that your chamber is reasonably tight compared to my NoMk1/2. I stopped using Remington because I'd start to see the "ring of death" and occasional seperation around about 5 reloads. PPU is better, but sure what the maximum is yet. I mixed up the brass when full length sizing to suit all the rifles.
Do you think the the chamber diameter may play more of a part than chamber length?


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It's nice to be important, but it's more important to be nice!


Posted By: britrifles
Date Posted: May 11 2020 at 4:47am
Yes, chamber diameter probably does play a role as the case head cannot expand radially right above the head.  However, a circumferential crack indicates longitudinal strain is excessive.  

In a pressurized cylinder, radial strain is two times higher than longitudinal strain.  As the chamber pressure builds, the case first radially expands to grip the chamber walls.  As pressure further increases, the case will expand longitudinally. The area just in front of the rim where the case can’t radially expand to fill the chamber (Restrained by the head) will elongate.  You often find that about 1/4 to 1/2 inch above the rim, the case has expanded larger in diameter than at the rim).  The chamber is conical while a new case has a small section that is constant diameter just above the rim.

The result is a small section of case web will plastically strain lengthwise until it contacts the bolt head.  This thins the web area.  Higher pressures make this worse as the bolt compresses and the action elongates (elastically of course).  Excessive headspace, and the case can rupture on the first firing.  This is why there is a maximum headspace specified.  The military did not have to worry about reloading, as long as the brass held for one firing and did not rupture.  You won’t get many reloads with headspace set to 0.074 field length.  

Someone made a cartoon video of this on another forum, very useful explanation.  




Posted By: Honkytonk
Date Posted: May 11 2020 at 6:12am
I have a No5 and use H4895 (36 grs) with 180 gr Sierra ProHunters and have no problem keeping shots at the range in a 6" bull @ 100 yds. Plenty good for the type of deer hunting I do. 


Posted By: The Armourer
Date Posted: May 11 2020 at 6:54am
Originally posted by britrifles britrifles wrote:


The result is a small section of case web will plastically strain lengthwise until it contacts the bolt head.  This thins the web area.  Higher pressures make this worse as the bolt compresses and the action elongates (elastically of course).  Excessive headspace, and the case can rupture on the first firing.  This is why there is a maximum headspace specified.  The military did not have to worry about reloading, as long as the brass held for one firing and did not rupture.  You won’t get many reloads with headspace set to 0.074 field length.  

Someone made a cartoon video of this on another forum, very useful explanation.  




The critical dimension is not really headspace at all - it is Head clearance and case rim thickness.

This is particularly noticeable when using thin-rimmed cases from Win and Rem, when compared to using 'quality' cases such as Prvi Partisan.

If you have a 74 thou 'headspace' using PP cases with (say) 62 thou rims, then change over to Win with 55 thou rims you have effectively increased your head clearance by another 7 thou to 19 thou (meaning the case 'web' now has to stretch 19 thou !

Because of the very thin case walls in the Win / Rem / SAMMI cases it is even thinner in the very area that is having to stretch.

look at the differences in case / rim dimensions :







The guy's name was / is Parashooter.



Posted By: The Armourer
Date Posted: May 11 2020 at 7:25am
It is interesting that 'we' consider headspace to be so important - is this solely because we are reloading, or is it because non-military cases are 'made to a price' and are very thin walled and thin rimmed ?

The UK Military considered that the LE was safe to shoot Military specification cartridges and authorisation was given to keep them 'in service' with a headspace of up to 0.080" (80 thou)





Posted By: Goosic
Date Posted: May 11 2020 at 8:46am
I for one do not worry about headspace The Armourer. You have a rimmed cartridge and it can only move x amount backwards upon firing. My question to britrifles was to learn how he is getting up to 50 reloads with the same brass and I can only get a max of 7 reloads before my cases start separating. I have just made an assumption that it is due to the generous chamber area designed into the Enfield and the repeated stretch of brass in that generous chamber area leads to case separations after so few reloading sessions. 


Posted By: The Armourer
Date Posted: May 11 2020 at 8:53am
Originally posted by Goosic Goosic wrote:

I for one do not worry about headspace The Armourer. You have a rimmed cartridge and it can only move x amount backwards upon firing. My question to britrifles was to learn how he is getting up to 50 reloads with the same brass and I can only get a max of 7 reloads before my cases start separating. I have just made an assumption that it is due to the generous chamber area designed into the Enfield and the repeated stretch of brass in that generous chamber area leads to case separations after so few reloading sessions. 



I understand that - I am up to about 10-12 reloads (a few maybe more) using PPU.

Headspace is "within spec" but not especially tight. I was simply showing that having an excessive headspace with thin walled and thin rimmed cases is likely to reduce the number of reloads due to taking the web area of the case beyond its elastic limit.

The only separation I have ever had was with S&B cases on the 2nd reload (third firing) and I know of some that have had them split on the 1st reload. They are 'rubbish'.

'Good' headspace and 'good cases' makes for 'good reloads'.


Posted By: britrifles
Date Posted: May 11 2020 at 8:59am
Tight headspace + thick rims = many reloads. That’s what has worked for me. 

Minimize the clearance between bolt face and rear face of case head.  


Posted By: britrifles
Date Posted: May 11 2020 at 9:05am
I should have also added “thick case webs”, as this is also likely a factor, although strain (deflection) is the failure mode. Additional thickness only helps so much, the case web will still strain the same amount until it is stopped by the bolt head. 






Posted By: Goosic
Date Posted: May 11 2020 at 10:10am
It is interesting to note here that. I can actually get more reloading sessions out of the 7.62mm Lake City brass if I dedicate that brass to my No4Mk2 with the 2A1 barrel as opposed to my M700P. I full length resize the 308 brass after every firing and the brand new Remington will end up with a case separation (without fail)🙃 after the third reload whereas the No4Mk2 will not see any case failure until the 7th or at the most,the 8th reload. 


Posted By: philtno
Date Posted: May 11 2020 at 1:16pm
The very first set of cases I used were PPU (my very box of rounds I bought more than a year ago).  I may have reloaded them around 20 times now with no case issues.  Same for the HXP which I may have reloaded even more times for some of them, only one partial case head separation and maybe 3 to 4 split shoulder over a batch of 150 cases batch.  I only full length-size them when the bolt becomes hard to close. Other than that, I only neck size them either with the Lee Loader (takes time but it's fun LOL) either with the hand press and the neck sizing die... I use light to medium loads.


Posted By: Honkytonk
Date Posted: May 11 2020 at 3:26pm
I also has switched to PPU brass exclusively. I've probably reloaded each brass 5x so far with no issues. I think maybe when I was stupid and "felt the need for speed" and pushed the upper limits of max powder specs, that was when I experienced failures after two or three reloads.


Posted By: britrifles
Date Posted: May 12 2020 at 6:20pm
 A simple calculation shows the axial (longitudinal) stresses in the .303 cartridge case just in front of the case head will be approx 120,000 per sq inch (at a nominal 40,000 psi chamber pressure).   That far exceeds the yield strength of cartridge brass, by as much as 10x, depending on the temper of the brass. This is why headspace is important, if it is excessive, the cartridge will rupture, that is a mathematical certainty. Do you need to worry if it is at the maximum of 0.074? No, but you will get lost life from your brass.  

The bolt head prevents the brass from failing in overload in the axial direction while the chamber prevents it from failing in radial (hoop) overload.  Axial overload causes circumferential cracks (i.e. case web cracking leading to a head separation) and hoop overload causes lengthwise cracking (i.e split necks or along the case body).  Chambers that are large radially would cause lengthwise cracks, not circumferential cracks.

Unless the head clearance (space between bolt head and back of cartridge) is very small, the case will plastically deform under the pressure of firing the cartridge.  The strain causes the cross section just in front of the solid head to neck down as the brass continues to elongate under the load, and the effect is cumulative with each firing, especially so if you FL size.  The only way to slow this process down is to minimize the head clearance (reduce headspace, increase rim thickness or reduce load pressures).  

The case rims of my 1943 Defence Industries Mk 7 service cartridges measures 0.063 to 0.064.  The headspace on my No. 4 rifles is just slightly larger, about 0.065.  This gives only 0.001 to 0.002 head clearance.  I believe this is why my DI 1943 brass lasts for 50 reloads.  Final head separations invariably occur after I have FL sized.  

The Long Branch No. 4 Mk 1/2 I just refinished has the headspace set to 0.064.  The bolt just fully closes with no fore/aft movement when locked on the GO gage.  I fitted a No. 3 bolt head to get this headspace measurement.  

Photo below shows the typical region of case web necking (thinning) from axial tensile overload. 



Canadian DI 1943 Mk 7 service cartridge rim thickness, right at maximum, 0.064 inches.






Posted By: Goosic
Date Posted: May 12 2020 at 7:21pm
My headspace is as it would have been directly out of the factory door. I cannot locate any Mk7 cases and as such,I have to use the cases I currently have that have an average rim thickness of 0.0625". I have no fore or aft bolt movement with a GO gauge installed.  The LB barrel is the one I found still wrapped in wax. The rifle itself shoots superbly and all of my reloads are charged with the minimum weights listed for my powder of choice. The headspace for my Savage No4MkI* is as it should be as well with the aforementioned nonexistent fore or aft bolt movement as well. My issue is not with headspacing. 


Posted By: Stumpkiller
Date Posted: May 12 2020 at 8:10pm
Originally posted by The Armourer The Armourer wrote:

It is interesting that 'we' consider headspace to be so important - is this solely because we are reloading, or is it because non-military cases are 'made to a price' and are very thin walled and thin rimmed ?

Major G. Nonte, Jr. in his excellent "Modern Handloading" described it as "Chamber Slop".  Not so much a headspace issue as a generous chamber bored out to allow a cruddy, sandy, iced up cartridge to chamber.

But must of us, as individual shooters, do not have a well funded war department to supply us free cartridges for single use; or anything with a suitable hunting bullet.  So we church-mouse poor reloaders seek to squeeze out as many reloads as possible.  Worse, some of us are in draconian oppressive government controlled isolation from resupply (like New York State for example) and loaded cartridges or reloadable brass can be precious indeed. 

Actually - new brass is readily available - for a price.  Primers, bullets and powder may be a bit "iffy" as some retailers will not ship to any part of NYS because of the damn "SAFE Act" that, supposedly, only prevents citiots ("city- idiots") from buying components in the five boroughs around New York City.  10% of the surface area of NY (where 95% of the population clusters) makes the other 90% suffer.




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Charlie P.

Life is not about how fast you run, or how high you climb, but how well you bounce.


Posted By: Goosic
Date Posted: May 12 2020 at 8:37pm
I will agree with the chamber slop. I will not agree when I am questioned in regards to my headspacing. I reload to exacting standards and have never  loaded to any maximum charge weights. I have resolved to chalk this up as luck of the draw and I have a very large supply of sh*tty brass...


Posted By: britrifles
Date Posted: May 13 2020 at 6:40am
Goosic, I’m not questioning you or your rifles.  I apologize if it came out that way.  

I made an attempt to explain why headspace is important, particularly if you reload.  Your issue does likely come down to commercial brass, it’s already thin in the web area when new.   You asked me what my secret was for long case life, I gave the best answer I could based on my experience.   That’s all. 

I check headspace on a LE rifle I purchase, bolt heads can get swapped out.  The one I just got was about at the field limit with a # 1 bolt head and I doubt it was issued that way after the FTR which included a barrel change.   Either headspace increased with use or a previous owner changed out the bolt head (wanting a #3 head perhaps).  

I’m having trouble understanding how radial expansion Into the chamber causes a circumferential crack, anyone have a theory on that?  

If you have PPU brass, let’s track how many reloads we get in our .303 rifles, this will eliminate the brass as a variable.   In my LB Mk 1/3, I have about 5 to 7 reloads, that’s just an estimate, but I’ll track this from now on.  In my Mk 1/2, just one reload, so I’ll be able to accurately track it.  






Posted By: Goosic
Date Posted: May 13 2020 at 6:56am
No worries britrifles. 
My brass of choice currently is this so called Canadian Mfg stuff. Unfortunately for me,I have 1000 rounds of it. I have been loading 100 rounds at a time. After 5-7 reloads,I typically will find 20-25 separated cases. I segregate each batch and tally how many reloads that batch has gone through. Still cannot get past the seventh reload without a case failure...


Posted By: Shamu
Date Posted: May 13 2020 at 7:22am
"Major G. Nonte, Jr. in his excellent "Modern Handloading" described it as "Chamber Slop".  Not so much a headspace issue as a generous chamber bored out to allow a cruddy, sandy, iced up cartridge to chamber."
Thank you, I've been looking for the correct term for that for a long time. For the rimed .303 headspace stops immediately in front of the rim's front face, but I never heard that term before.


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


Posted By: britrifles
Date Posted: May 13 2020 at 8:06am
Originally posted by Goosic Goosic wrote:

No worries britrifles. 
My brass of choice currently is this so called Canadian Mfg stuff. Unfortunately for me,I have 1000 rounds of it. I have been loading 100 rounds at a time. After 5-7 reloads,I typically will find 20-25 separated cases. I segregate each batch and tally how many reloads that batch has gone through. Still cannot get past the seventh reload without a case failure...

Goosic, next time I fire some DI 43 Mk 7z ammo, I’ll send you the cases to try.  I’m very interested in finding out exactly why I seem to get so many reloads and others do not.  I have run some too long, even a few more reloads after the white line of death appears.  

PPU does seem to be closer to military specification, so perhaps it will last longer.  

I’d also suggest sectioning a case and measure the thickness of the case body.  My Mk 7 cases all crack 0.32 inches from the back of the head where the web thickness measures about 0.032 in.  I need to confirm this thickness on an unfired case.


Posted By: britrifles
Date Posted: May 13 2020 at 9:05am
 We kinda drifted from the original topic, but here is a photo of an unfired (on left) and a cracked (on right) DI 1943 Mk 7 case that is sectioned.  The case web cracks occur at 0.32 inches above the Bottom surface of the head.  The web thickness at this location on a new case measures 0.035 inches thick.  

The unfired case weighed 168.4 grains, 2.207 inches long, 0.452 inch diameter just above the rim and a 0.064 thick rim.  




Posted By: Zed
Date Posted: May 13 2020 at 10:22am
Britrifles, regarding your question on how a radial expansion can cause a split on the circumference.
Is it possible that the case is working in two directions in this area when fired? 

If the chamber is a bit large in the diameter. (which seems quite common in LE's) As the powder chamber area of case expands outwards to grip the chamber wall, the rim end of the case will move rearward to take up any slack in the head space as we know; but the case in front of the reinforced area around the primer will also expand outwards. The ring appears at the join of the stronger rim area and the powder chamber case thickness. Could this explain the difference in number of reloads in rifles that have known good headspace?

On one of my rifles I get the impression that the cases do blow outwards slightly at this area. Cases from this rifle do not chamber in the other's.
I'll have to measure them after the next range trip; all my brass is resized and waiting for the range to open at the moment.

With regard to the original poster asking about the "O"ring method. I suggest he reads Peter Laidler's opinion on that. You certainly don't need "O"rings if the rifle headspace is good; and if the headspace is out of specification with the largest bolt head; then it's probably the receiver thats worn out. But the tool for checking that is probably impossible to find!


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It's nice to be important, but it's more important to be nice!


Posted By: britrifles
Date Posted: May 13 2020 at 12:21pm
Zed, 

There is certainly bi-axial stress in the case from the internal pressure.  When the case yields in the radial direction (which occurs first since the hoop stress On the case is 2x the axial stress), it will first pull the head forward and take up any head clearance.  But as pressure builds, and radial expansion is restrained by the chamber,  the case head will then get blown back firm against the bolt.  It is this plastic axial overload strain on the brass that causes the thinning (“necking” is the technical term).  You will see in the photo above that it occurs above the juncture of the web and solid head area, not at it.  The exact location of the necking will likely vary somewhat depending on specific case dimensions.  

This is not a fatigue crack, the thinning (necking) is an overload rupture failure from exceeding the materials yield (and ultimate) strength.  

In reality, it is probably more complex than this involving localized bending stresses at the juncture of the case head, as you pointed out, the chamber diameter is considerably larger than the case and the case head restrains radial expansion at this point. The length of the case that has not firmly gripped the chamber also plays a role, so another effect of chamber geometry.  

I’m no expert, not trying to insinuate I am, just applying some basic engineering principles to the problem.  

How much of this is also influenced by the rear locking lug design would take some calculation (how much the bolt compresses under load) but that’s just more than we need to know.  Reload until you see the white line and then toss the case.  If your fortunate to have some spare bolt heads, try to minimize the head clearance based on the brass you are using.  But, I would be very careful in reducing headspace below minimum (0.064), this could result in not being able to lock the bolt on a thick rim cartridge, that would be potentially dangerous.  






Posted By: Zed
Date Posted: May 13 2020 at 1:08pm
I tossed a lot of Remington cases when seeing the ring appear. After having one or two heads seperate, you learn quickly to spot the fault line.
I must say that I'm much happier with the PPU cases.
The last bag of Remington that I bought appeared thinner than the older ones; especially around the neck area. I have not loaded any of this bag; having just stored them since moving on to the PPU's. I'll try and measure both old and new Remington cases and compare.

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It's nice to be important, but it's more important to be nice!


Posted By: Shamu
Date Posted: May 13 2020 at 4:00pm
I've never had a case "let go" there!
I have had cases separate, but its further forward?
Several rifles, multiple brass brands & decades of shooting?



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


Posted By: britrifles
Date Posted: May 13 2020 at 4:06pm
I had 200 RP cases I bought about 20 years ago.  I’ve not used them much, I reloaded these for my Dad’s No. 4(T), maybe 8 times now, no issues yet.  The barrel on this rifle is a Long Branch six groove RH twist that hadn’t had many rounds thru it.  

RP cases had not available for a while so when I saw them listed again recently I bought a few hundred, haven’t looked at them yet.  

I weighed a number of PPU cases, average was 170 gr. IIRC.  Comparable to the Mk 7 cases I have.  


Posted By: paddyofurniture
Date Posted: May 13 2020 at 4:10pm
Do nickel plated cases last or do they crack and die?

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Always looking for military manuals, Dodge M37 items,books on Berlin Germany, old atlases ( before 1946) , military maps of Scotland. English and Canadian gun parts.


Posted By: Shamu
Date Posted: May 13 2020 at 4:12pm
In my experience they are terrible. I don't know why. I only use them as "fire & forget" ammo. now to be fair these are all Remington nickle cases, others may be fine.
I used to be a big fan of Remington Brass. No longer unfortunately Prvi Partizan has them hammered on both quality & price.



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


Posted By: MJ11
Date Posted: May 13 2020 at 6:47pm
Well this has been an interesting post.

Without pulling my log book I can't remember getting 3 reloads out Remington brass. They were normally dis guarded after two loads after feeling the inside of the case head and web area with a small bent probe. You could locate the failure line by feel and then you would recognize the area out side from then on and the dis guard number rocketed up. Winchester was equally bad. Lapua was good but I have only shot them four times so I can't put a real limit there.

Tonight reading this I pulled out my Brown & Sharp calipers calipers I got when I graduate the Small Arms course at Armament Command school in 1966. Locked up from lack of use. Thirty minutes later after a careful cleaning years over due I got a .059" rim on my much vaunted Greek HXP 1976 ball.

As an aside I once took my 7.62X51 Enfield to a match with once fired LC Match brass with the little band of knurling 1/4" above the extractor  grove. Second shot in the match at 200Y the case head came off right there leaving the LCM case in the chamber. Both rounds had been in the 9 ring side by side with iron sights. But I was out and that ghost played he!! on me for a long time. by the time I cleared the stuck case it was time to pack up and go home. I stayed and put ten ten rounds of some Spanish .308 cases that had been through my HK 91 loaded for 500 Y + eight times. I had five bulls and a few nines and eights. The HK is brutal on brass with the gas serrations and violent ejection cycle. Ca-rumba I miss that rifle. But it worked well in my #4 7.62 Enfield. It's crap shoot out there boys.

I have some PPU 303 coming for the three new to me rifles this week. I will be interested in the results run side by side with new 174g HXP and 174g PPU and then the reloading comparison.

While I'm not an expert on anything the results should be interesting to some degree. 

Another note maybe ten years ago I bought 400 PPU bullets called .311" 174g Match. They were anything but . The weight was all over the map from 167g to 175g and I never had two shots fall within 1.5 MOA of the last when we still had the 200Y line open at the same time as the 300Y and 500Y steel plates. I was careful with assembling that I gave up and just went with the average from then on and worked on my job. A hit is a hit restored my faith in the #4.

I hope this post grows because I will watch it and learn from all the experts.

Cheers

200Y



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The Spartans do not ask how many the enemies are but where they are


Posted By: britrifles
Date Posted: May 14 2020 at 4:51am
Interesting MJ.  I may have been lucky with the small batch of RP cases I have.  I don’t think I’ve had to FL size them yet.  They have so far held up well in Dad’s No. 4(T).  Next time I’m up in Ontario, I’m going to check the headspace on this rifle.  It was done by a very competent DCRA Armourer in Ottawa back in the ‘60’s, so I expect it is right at minimum.  

I measured the rim thickness on my RP cases at 0.059 to 0.060.  I don’t expect they will last as long as my Canadian military cases.  




Posted By: 303Guy
Date Posted: July 08 2020 at 2:22am
If I may make a comment, realizing the thread is a few months old but head separation and case life in the Brit is a function of smoothness of the chamber and dryness of the loaded case.  Lube the loaded cases and they will last forever.  Dry them and expect three to five loadings.  

Lubing means rolling them lightly on the lube pad.  This does not prevent case wall grip but does limit the grip, allowing the case to elongate over the full body length while the neck itself does not move.  This practice prevents case elongation and doughnut creep.  It does not increase bolt face thrust as there is not enough lube to float the case.  There is still a degree of bolt face thrust reduction though, about as much as a dry case provides on first firing.

The fact that the case wall is elongating and thinning means the case is not carrying as much thrust load since the case is actually progressively failing on each firing with progressively less thrust reduction, as little as it was to start with.  The maximum thrust a case can carry is the stress area of the case wall, which once it reaches yield point drops off because the material has failed, i.e. undergone plastic deformation.



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303Guy


Posted By: britrifles
Date Posted: July 08 2020 at 7:22am
I’ve never lubed the cases, and I typically get 50 reload cycles on military brass.  I haven’t reloaded any commercial cases more than about 10 or 15 times, so I don’t know yet how long it will last.  

I do the opposite, I make sure the cases are clean, free of lube, and the chamber is clean and free of oil/grease.  I wrap a patch around my chamber cleaning rod and apply some brake cleaner to degrease the chamber before every range session.  I’ve shot many thousands of rounds this way in my LEs, no measurable change in headspace and long brass life.  

This ensures the case is gripped by the chamber and bolt thrust loads are reduced.  But, if you have relatively large headspace, it will overwork the brass particularly if you FL size.  You want to neck size only to get the case to headspace on the shoulder.  Then the only displacement of the case in the axial direction is due to elasticity of the bolt and receiver under load.  

Minimizing bolt thrust loads reduces the fatigue loading of the bolt lugs and bearing stresses on the lugs.   
If your loads are relatively mild, then light lube likely does no harm over the long run.  But, I’ve found the process I use works for me.  




Posted By: Shamu
Date Posted: July 08 2020 at 9:09am
I have a bunch of HXP & PPU (nny) brass, much of it is on its 6th full power load.
I usually "partial Full Length resize", & anneal the neck after the second trimming to length.

Remington used to be nice, it was my preferred brand, but quality dropped massively over the last few years now I won't touch the stuff, much preferring the PPU (nny) or HXP when I can find it.


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


Posted By: Zed
Date Posted: July 08 2020 at 9:59am
With all due respect 303Guy. I won't be lubing any of my rounds. All official documentation says not to. 
I'd rather throw away a cracked case than a cracked receiver! These rifles are old; some have seen a lot of action; no point over stressing the old girls just to save a few quid.


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It's nice to be important, but it's more important to be nice!


Posted By: britrifles
Date Posted: July 08 2020 at 11:18am
Zed is right of course, I just didn’t want to drag out this argument, it caused a blow out and banning of a member over on another forum, a hot topic.  Which is why I said it’s likely OK for light loads, given that bolt thrust increases by about 40% with the case immersed in oil and immediately chambered.  

Lubing cases even changes the MPI on the target indicating the action is flexing more with lube.  See Reynolds book, he gives the test data on this.  


Posted By: Goosic
Date Posted: July 08 2020 at 11:45am
A form of hydraulics and not the good kind. britrifles,  you would not be dragging this out,just solidifying what is already known about lubed cases in a rifle chamber.


Posted By: Honkytonk
Date Posted: July 08 2020 at 12:39pm
I used to work in the natural gas compression and refining business. We had 6500 hp multi stage recipricating gas compressors, pressuring the gas up to 5000 psi. I've seen piston rods 6" in diameter snap like a twig ifslug of water gets into the cylinder. I've also seen a 5 ton cylinder block crack due to water. You cannot compress a liquid (water, oil, etc) Something else will fail first...


Posted By: Goosic
Date Posted: July 08 2020 at 12:50pm
We hydrauliced a cylinder on purpose in auto shop to see if we could get the 6 cyl inline Ford engine to destroy itself.  Removed the rocker arms from the #4 cylinder and used a high pressure pump to inject water into the cylinder as the engine was running. The crankshaft hit the floor in two pieces 



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