Print Page | Close Window

how to use headspace gauge?

Printed From: Enfield-Rifles.com
Category: Enfields
Forum Name: Enfield Rifles
Forum Description: Anything that has to do with the great Enfield rifles!
URL: http://www.enfield-rifles.com/forum_posts.asp?TID=5245
Printed Date: March 28 2024 at 5:12am
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com


Topic: how to use headspace gauge?
Posted By: AussieInUtah
Subject: how to use headspace gauge?
Date Posted: June 02 2012 at 1:40pm
While shooting my Ishapore SMLE No1 MkIII last weekend, I had a case head separation which left the front part of the case stuck in the chamber of my rifle.  Not fun.  Had to get a gunsmith to fish it out for me.  One of the other cases I'd shot that day developed a similar crack, but didn't fully separate.

The case had been reloaded about 4 times, maybe 5.  The load was 41.8 gr Varget behind a 174 gr SMK HPBT.  I don't think that is an excessively hot load.  It gives a muzzle velocity of 2480 fps.  The cases are made by Winchester.

This is the first time I've had a case head separation in this gun.  The gunsmith said that the cases might be getting excessively stretched because I have excessive headspace.

So I bought Go and No Go gauges from Forster.  Only problem is that the case extractor is catching on the gauge so I can't close the bolt on either of them.  What to do?  Am I supposed to remove the extractor from the bolt?  How do I do that?

Should I also get a Field gauge?

Are these Forster gauges what I need, or should I be getting a different brand?



Replies:
Posted By: SW28fan
Date Posted: June 02 2012 at 3:42pm
You Need to Slip it on the bolt with the rim under the extractor like you were chambering a round from the magazine.  Numrich Arms has rather modestly priced 303 Broken She!! extractors. 
Sometimes inserting a fresh round into the chamber will catch the broken cases enough so you can extract it. 
 
One question were you Neck Sizing or full length sizing? Neck sized cases hold up much better.
 


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


Posted By: LE Owner
Date Posted: June 02 2012 at 10:51pm
I've always heard its best to remove the extractor when using a headspace gauge, and pushing the gauge out with a cleaning rod if necessary. Some prefer to remove the firing pin and spring as well.
You must not force the bolt closed, which is a good reason to remove the firing pin and extractor, since either causes significant back pressure on the bolt when closing.
 
Removing the extractor is easy, just take out the screw and pull the extractor out. Getting it back in can be a problem due to the stout little V spring.
I'll see if I can find proper instructions for you.
Try this link
http://www.scribd.com/doc/2469267/Enfield-No4-Bolt-Disa$embly" rel="nofollow - http://www.scribd.com/doc/2469267/Enfield-No4-Bolt-Disa$embly
 
I'm all for tightening headspace by replacing bolt heads with a higher number, but few #2 and fewer #3 boltheads are out there these days. #1 boltheads are available from several vendors.
Also since over long boltheads were sometimes sanded to fit many no longer measure the length indicated by the number.
To some extent a bolthead may compress by a few thousandths after many thousands of rounds.
A new old stock bolt head of the same number as the bolthead now present may be a few thousandths longer simply because it hasn't been subjected to repeated firings.
 
A new condition bolt body if available might be the answer.
These are available for the SMLE (No.1) but I've not seen these listed for the No.4. 
Bolt bodies require careful hand fitting to insure even locking lug contact.
 
 
PS
If using Seller & Bellot cases those are a problem and are the least durable when reloaded.
Many have recommended Privi Partizan as the best case for reloading.
 
To get the most reloads from every case, and the best accuracy as well, I mark case rims and after first firing neck size only then rotate the case 180 degrees when firing for the second time.
This insures equal expansion of the case, which will help in presenting the bullet to origin of rifling without cant.
I also only size 2/3rd of the neck. The equally expanded unsized rear portion of the neck also insures proper presentation of the bullet.
Try this and you may find group sizes are immediately cut in half.
Seating bullets out far enough to take up the slack in the distance to OR in the throat also reduces group sizes remarkably.
I prefer the 150 gr Hornady .312 bullets. These if seated to the crimping groove give a short OAL. I instead seat these to the full OAL which leaves the crimp groove exposed. You may not need to seat them that far out since some barrels have more or less slack in the throat. You do not want to seat them too far out as this can raise chamber pressure.
 
I don't crimp.
The less the pull strength on the bullet the less the effect of variations in pull strength.
It depends on how tight the case neck grips the bullet, since you don't want to risk a bullet being pushed deeply into the case, which can cause serious (sometimes disasterous) pressure increase.
 
 


Posted By: AussieInUtah
Date Posted: June 03 2012 at 5:05am
I can't slip it onto the bolt with the rim under the extractor.  That doesn't work.  I'm going to have to remove the extractor.  I looked at the instructions that LE Owner pointed me to.  They are for a No 4 rifle.  I have a No 1 Mk III.  Is the procedure the same?

I was using an RCBS neck sizing die.  That is one reason why I am unhappy about the short case life in this rifle.

Because I have a No 1 Mk III, I can't replace the bolt head to adjust headspace.  That only works on No 4 rifles, as far as I am aware.  What other options are available?


Posted By: Lithgow
Date Posted: June 03 2012 at 9:34am
Yep the procedure is the same for both the No1 and No4 bolts.
You can replace the bolthead on the No1 to correct headspace but you will need to have the correct length bolthead. It is handy to have a good selection. Measure the length of the one you have and look around for a longer one.
Since you are using Forster guages you will find that your headspace will most likely be out of spec as mil spec guages are not the same as SAAMI guages.
The correct method is to remove the extractor, the reasoning behind this is that it can damage the headspace guage and raise burrs on the guage which in turn could give fals readings.


Posted By: AussieInUtah
Date Posted: June 03 2012 at 11:11am
Well that screw holding the extractor on the bolt head isn't coming out.  I damaged it trying to undo it, and gave up before I completely buggered it.  It's stuck.  I give up.  Whatever the headspace is on that rifle, I'm going to have to live with it.


Posted By: Canuck
Date Posted: June 03 2012 at 12:07pm
Try soaking the bolt head in penetrating fluid, for like a week, then try loosening the bolt again. If it doesn't come out, it will have to be drilled out by a machinist or gunsmith then replaced. Other than that, you might have to be happy with the headspace you have.


Posted By: LE Owner
Date Posted: June 03 2012 at 12:08pm
Originally posted by AussieInUtah AussieInUtah wrote:

Well that screw holding the extractor on the bolt head isn't coming out.  I damaged it trying to undo it, and gave up before I completely buggered it.  It's stuck.  I give up.  Whatever the headspace is on that rifle, I'm going to have to live with it.
 
Well since the cases that cracked were Winchester made and reloaded and fired 4 or more times your rifle probably has fair headspace compared to most Enfields.
The Winchester cases have a well earned reputation for not lasting long when fired in the standard Enfield .303 milspec chamber, and the fairly thin rim is only one reason for this.
 
Remington cases work well in my rifles, though mainly because I corrected headspace by fitting new bolt bodies and boltheads.
Some Winchester cases have split long ways on first firing in some rifles that have had no problems with other brands. These were likely a rare instance of defective cases, but that put me off Winchester bra$ for good. Even Winchester cases that showed no damage on first firing have not lasted as long as the Remington case in my rifles.
 
Use a different brand case and try out the tricks I mentioned, which should improve accuracy and increase case life.
You might also try the thin O-ring or fishing line method for first firing to fire form to the chamber then neck size only. That way the reloaded rounds headspace on the shoulder instead of the rim.
The O-ring or ring of monofilament placed ahead of the rim takes up the slack , holding the case head against the bolt face to avoid case stretching.
Many swear by the O-ring. I haven't tried it because my rifles have excellent headspace and tighter than average chambers.
 
PS
There are headspace gauges that have a clearance cut so the extractor does not touch the gauge.
Also Commercial .303 gauges are thinner at the rim than British Milspec gauges.
The max milspec headspace of .074 is okay for safe shooting, but leaves too much slack (headgap) to expect reloadable cases.
The fresh from the factory milspec headspace at .067 or less would be well within that needed to produce reloadable bra$ without resorting to use of an O-ring, so long as you start out with good bra$.


Posted By: AussieInUtah
Date Posted: June 03 2012 at 12:23pm
I think that I'll try to obtain a set of No1 MkIII bolt heads in different dimensions.

That screw probably won't come out, even with extended soaking.  I'll just toss the entire bolt head as soon as I find a replacement that works.

That Winchester bra$ has a flimsy feel to it.  I'll try the Remington bra$.  The Privat Partizan bra$ that I've reloaded for my Mosin-Nagant seems good quality, so I'll try that too.


Posted By: SW28fan
Date Posted: June 03 2012 at 1:38pm
A quick note on Winchester 303 bra$  IT SUCKS  it is slightly better than  S&B but not by much the best is Privi followed by Norma then Remington. 

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


Posted By: Shamu
Date Posted: June 03 2012 at 10:18pm
Originally posted by SW28fan SW28fan wrote:

A quick note on Winchester 303 bra$  IT SUCKS  it is slightly better than  S&B but not by much the best is Privi followed by Norma then Remington. 
This cubed.
You might try the Okie Gauges headspace gauge it's a coin type, designed to work with both the firing pin & ectractor still fitted, it has a cutout for both so you won't harm anything & is to MOD specs, not SAAMI.


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


Posted By: Alan de Enfield
Date Posted: June 16 2012 at 3:27am
Measure your rim thickness on the Winchester brass (probably around 0.056"-0.058". Then measure the rim thickness on the Privi brass (probably 0.060", maybe even 0.062").
 
You can tighten your (effective) headspace by 3 or 4 thou just by using quality cases and not 'cases built to a price'. - which unfortunately Win, Rem and S&B seem to do.
 
If you cannot get hold of original Mil-surp brass (HXP is the best) then get the best you can (Privi). I'm on the 10th reload (11 firings) for some of my Privi brass for all my Enfields (No1, No4, No4T and No5)
 
Just remember that Enfields pre-date SAMMI by a long way, SAMMI impose non-realistic dimensions on 'old' firearms so they can acommodate todays litigious society with safety.


-------------
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: June 16 2012 at 9:17pm
Originally posted by Alan de Enfield Alan de Enfield wrote:

Measure your rim thickness on the Winchester brass (probably around 0.056"-0.058". Then measure the rim thickness on the Privi brass (probably 0.060", maybe even 0.062").
 
You can tighten your (effective) headspace by 3 or 4 thou just by using quality cases and not 'cases built to a price'. - which unfortunately Win, Rem and S&B seem to do.
 
If you cannot get hold of original Mil-surp brass (HXP is the best) then get the best you can (Privi). I'm on the 10th reload (11 firings) for some of my Privi brass for all my Enfields (No1, No4, No4T and No5)
 
Just remember that Enfields pre-date SAMMI by a long way, SAMMI impose non-realistic dimensions on 'old' firearms so they can acommodate todays litigious society with safety.
 
I doubt that scrimping on brass is the real reason why so many commercial sporting cartridge cases for the .303 have thinner rims than milspec cases.
IIRC .056 is the original minimum rim thickness.
The .30-40 Krag has the same max rim thickness as the .303, at .064 , yet the U S Army manuals for the Krag list rim thickness at .060.
Overly thick rims were a serious problem with WW1 .303 ammo, requiring gauging of rims to ensure proper functioning of the Maxim and Vickers MGs.
A collector of British double rifles once told me that his .303 rifle would not close on the available .303 milsurp ammo due to that rifle having been built to the minimum commercial specs.
 
A too thin rim will only compromise the reloadability of a case, while a too thick rim will prevent tightly built sporting rifles from operating.
The U S manufacturers go by the minimum specs for sporting ammo, which is to be expected since it is sporting ammo.
There are relatively few rifles other than the Lee Enfields that are chambered for the .303, but if i owned a Model 95 Winchester in .303 and the ammo I bought for an expensive hunting trip would not chamber I'd be very PO'ed.
I'd be even more PO'ed if the ammo was loaded to 50,000 CUP and cracked or set back my bolt after a few dozen rounds, as happened to many 95 Winchesters when .30-06 pressures were raised from the WW1 standard of 48,000 to 50,000, and as happened to many Krag rifles when the Ball cartridge pressure was raised from 40K to 43K.
 
The WW1 era commercial specs for .303 sporting rifle headspace were minimum .064 and maximum .068.
The Lee Enfields were expected to have headspace of .067 or less after proof testing. The much looser specs of up to .074 were for rifles with significant wear.
 
If you can obtain boxer primed milspec cases you are ahead of the game.
If not then some attempt to return the rifle to minimum headspace value is in order if reloading is an important part of your shooting.  
 
After correcting headspace of my old Savage No.4 I have no problems with reloading Remington commercial cases.
Winchester cases I'd used in the past seemed more brittle and poorly drawn, which made reloading them unproductive regardless of rim thickness.
 
The cartridge companies often farm out and subcontract components, so its hard to be sure where these components may come from even if they do bear a headstamp.
 


Posted By: jorgen
Date Posted: October 05 2012 at 2:30am
go on line, and look on google for how to use the standard headspace gage with out removing the extractor.  it is easy.  take out the magazine, hold the bolt about 2/3rds of the way to home, push the gage up from the bottom, and pull the extractor back to slide the gage onto the bolt face.  position the gage like a cartidge would fit, and gently push home.  if positioned correctly on the bolt face, it will slide in.  don't force anything.  gently close the bolt, and gently rotate the cocking handle till the slightest resistance is felt.  I just did this.  I found a presentation at one of the forums with photos on how to do this a while back.  best regards, jorgen

-------------
jorgen


Posted By: hoadie
Date Posted: October 05 2012 at 3:53pm
Seems to me I gave Rhino a bag or two of PRIVI brass back in May.
Wonder if he's done any loadin yet?
Hoadie

-------------
Loose wimmen tightened here


Posted By: Canuck
Date Posted: October 06 2012 at 3:45am
Luckily, my rifles all headspace nicely on a .067 guage and I don't have to remove the extractor or it's spring to perform the task. Maybe it has to do with the guage itself? I use the cartridge style guages. It is a nice feeling to know your rifle(s) headspace properly and that the locking lugs engage all the way upon cocking. I haven't used PRVI ammo yet and have been using Win/Rem exclusively with good results on and off the paper. I have just gotten into reloading but only my handguns so far, but not including my 1939 Enfield #2/Mk1 tanker model, yet.


Posted By: John Sukey
Date Posted: October 06 2012 at 4:57am
Note Forester gages are SAMMI spec, NOT enfield spec.  SAMMI tolerances are tighter than British.
Also the british military were not into reloading
If you can find South African, Greek HXP  ot Privi brass, the quality is far better.
You might want to invest in a broken case extractor.  I keep one in my range box.
If you are reloading for just one rifle, neck sizing is the way to go.  If for more than one, keep some seperate for each rifle.


Posted By: AussieInUtah
Date Posted: February 04 2013 at 4:43am
Hope someone is still following this discussion.

I mic'ed my bolt head at 0.635" and wrote to one supplier to find out if they had one slightly bigger.  They came back with one that measures 0.640", which they said is only slightly shorter than a true oversized bolt head.  Price is $20 so not overly expensive.

Do you guys think that using a bolt head that is 0.005" longer than the one I've got will make much difference to case life in this gun?  To me, that doesn't seem like an awful lot of difference when it comes to case stretching.

I didn't have much luck with the Forster gauge.  Tucked it under the extractor claw after passing it up through the magazine well, but couldn't get it to feed into the chamber at all.  So I didn't even get close to seeing whether the bolt would close on the GO or NO-GO gauges.

Just put in my order for the broken case extractor.  Think this might come in handy if I keep shooting this rifle.  I've fired about 200 rounds through it, with only two case head separations, so it might just be a matter of buying good brass and not reloading it more than about 4 times.


Posted By: muffett.2008
Date Posted: February 04 2013 at 4:47am
Yep, that bolt head will make a difference.


Posted By: Shamu
Date Posted: February 04 2013 at 6:02am
Without knowing a measured headspace you won't know what you're fixing.
Will it tighten up the space between the breechface & the boltface when closed & locked?
Sure, by exactly 0.005".
 
Will that fix the brass problem?
Who knows?
 
How does the neck & shoulder dimension compare with an unfired case with both sitting on a flat surface vertically? Is the fired case's shoulder noticably blown forward, but everything else is fine? If so that indicates the problem is other than headspace, but you're still not absolutely certain.
 
The thing to remember here is that rimmed case headspace is the space available for the thickness of the rim, nothing else. So if your rim is slopppy & thats where the excess is coming from sure it'll help. Is it headspace, thin rims, or a combination of both? No-one knows till you have an actual measurement!
 
Even then because headspace is exclusively the rim what happens if the headspace & rim is 100% perfect, but the front of the chamber is excessively hogged out?
There's no way you can know except by eliminating rims & headspace so all that's left is the problem.
 
I'd try measuring headspace again, but with the extractor removed to make it easier. How to remove it?
Undo the screw, pop out the extractor & spring & shove a 1/4" dowel down the bore when measuring so you can ease the gauge back out again afterwards. Failing that can you guide the gauge into the chamber with a screwdriver or something similar to ease the first part entering & take extractor spring & claw pressure off the case base?
 
If you do go with removing the extractor, Re-installing is easy.
Insert the actual claw, pass the screw through & tighten (no spring). Now loop some strong fishing line through the "U" bend in the spring, pass the ends back to make a loop behind the head, insert a pencil or something into the spare line & pull hard. The spring will just pop back into place.


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



Print Page | Close Window

Forum Software by Web Wiz Forums® version 12.04 - http://www.webwizforums.com
Copyright ©2001-2021 Web Wiz Ltd. - https://www.webwiz.net