[69khz]

Got my Forsters 8mm headspace field gauge today.

On my Turk 1893, with the extractor attached, it passed as the bolt would not close.

However, when I retested with the extractor removed, I think it failed. The bolt didn't quite close all the way, but very nearly did, so I pushed down a bit harder & it closed.

Am I doing this wrong, or is almost closed but not fully closed on field gauge still make my rifle safe to fire factory or handloaded ammo?

First photo is bolt position on field gauge with extractor attached

2nd photo is bolt position on field gauge with extractor removed, but after, when I apply a little bit of force on it, it closes.

 

[Devo]

You're not supposed to use force, just light pressure with a couple of fingers.

-Devo

 

[Ike27]

If you reload, once the cases are fire formed the any minor HS should resolve itself.

 

[69khz]

If you reload, once the cases are fire formed the any minor HS should resolve itself.

I plan on learning reloading. I'm waiting for a book, manual & lee dies to arrive in mail.

I'll learn soon enough when the book comes, but in regards to fire formed, don't the full length sizing die put the case back to its previous unfired state?

 

[DudleyDR]

A "NO GO" or a "FIELD" gage is NOT supposed to close (hence the name, no-go) in order to "PASS" - and then you forced it to the closed, "FAILED" position. It was correct to check it without the extractor and bolt guts. Let it rotate with just the weight of the bolt arm and knob and check it with the lightest of pressure from a finger. Let it stop rotating where it "wants" to stop rotating.

Ike 27 is correct.

DDR

 

[69khz]

Thank you everybody.

I thought I had a dud..
It passes with only lightly trying to close.

 

[micmacman]

i had a mosin that didnt pass the test,it had a mismatched bolt,tried a bolt from another rifle and it passed,and the the bolt that didnt pass in the one rifle passed in the rifle that had the other bolt

are not some of these head space issues a result of bolts being swapped around over time haphazardly by importers and such? a result of heres a bolt that completes a rifle and stopping there,and selling the rifle?

 

[Vaarok]

New '93 bolts are only like twenty-five bucks, get a new one and try again.

 

[ab4ka]

sounds like you're ok. I used to get confused with the different gauges, that's why I just use a field gauge. I know as long as it doesn't close I'm good.

 

[jjk308 In Memoriam RIP]

I've tried bolt switching on 7 of my 1893 Turks, none of which had matching bolts. Almost no difference. The bolts flopped to a position very, very close to that of the "original" and the couple that had failed couldn't be made to pass with any of the bolts. I'd guess the reason was those obsessive-compulsive Germans making all the bolts nearly identical.

 

[Ike27]

69khz

There are 2 types of resizing. Neck and Full Length. If you are loading for a specific rifle. (not caliber, but rifle) then you can neck size which is basically just reforming the neck of the case to hold the new bullet. You will have a perfect case to fit the chamber of that particular rifle. If you are going to use the rounds in another rifle of the same caliber, if you reload for a semi auto, or when the cases are tough to extract (4-5 neck sizing’s) you will need to full length size.

 

[69khz]

69khz

There are 2 types of resizing. Neck and Full Length. If you are loading for a specific rifle. (not caliber, but rifle) then you can neck size which is basically just reforming the neck of the case to hold the new bullet. You will have a perfect case to fit the chamber of that particular rifle. If you are going to use the rounds in another rifle of the same caliber, if you reload for a semi auto, or when the cases are tough to extract (4-5 neck sizing’s) you will need to full length size.

Oh, thank you for the info.

The die kit I ordered is neck sizing die & here I thought I bought the wrong kit.
Perfect. Thanks for your reply, much appreciated.

 

[69khz]

Well, just discovered yet another problem.

My gauge is a 19° & I think I'm supposed to be using the older 20° one.

The barrel is dated 1936, so would this be 20° or 19°

 

[Ike27]

Here is my advice.


Load a round, put the rifle in a magnum vice secured to a shooting bench. Pull the trigger with a string. Examine the case for signs of pressure, headspace etc.

That will tell the story. And besides, you will be neck sizing so the first firing will be "fire forming"

 

[DudleyDR]

69khz: I think that you are mentioning a distinction that in all practicality will make no difference. Fire-forming will mate the brass to your chamber and your die will not work it too much in any case (no pun intended). Just pay attention to neck O.D., neck I.D. and case length - expect to trim the brass as it grows. DDR

 

[tjg79]

Well, just discovered yet another problem.

My gauge is a 19° & I think I'm supposed to be using the older 20° one.

The barrel is dated 1936, so would this be 20° or 19°

The original German WWII era 8mm Mauser chamber shoulder angle is 19° 6' 2.8''. Source: Mauser Original Oberndorf Sporting Rifles, Jon Speed, et al, 1997, page 276. Also, there is a September 16, 1941 K98k barrel drawing on page 94 of Backbone of the Wehrmacht, Law, 1993, which appears to be the same angle.

It appears the original German WWI era 8mm Mauser chamber shoulder angle is 18° 26' 5.8''. Source: 1915 barrel drawing, Rifle & Carbine 98, M98 Firearms of the German Army from 1898 to 1918, Dieter Storz, 2006, page 109.

Forster makes headspace gages to SAAMI specs. For the 8mm Mauser chamber, they make two different sets; one set to the current SAAMI spec with a shoulder angle of 19°, and one set to the obsolete SAAMI spec with a shoulder angle of 20° 48'. Indications are SAAMI changed the shoulder angle spec in 1980.

I don't know what the chamber shoulder angle is for a 1893 8mm Mauser chamber. You should do a chamber cast and measure the results.

Forster's headspace gages have a .006" difference between go and no-go. And .004" difference between no-go and field. From all the German barrel drawings I've seen there is no tolerance for length of the chamber from the shoulder datum to the bolt face. The Germans could hold .01mm. The Forster .006" difference between go and no-go seems sloppy. There is a difference between sporting arms standards (SAAMI & CIP) and original milspec. I wouldn't use Forster gages to fit a new barrel.

 

[Mike442]

First off, I notice in the photos that the bolt has not been stripped. The cocking piece, sleeve, firing pin and spring and extractor should all be removed before checking headspace. Also the chamber and bolt body should be thoroughly cleaned before checking headspace. Next place the gauge in the chamber and push the bolt forward, then let it rotate down under the weight of the bolt handle and knob only. A little pressure may be applied but should not exceed a few ounces.

You should be using the 19 degree headspace gauges if you will be shooting modern SAAMI spec ammo. Or if you have more than one rifle chambered in 8mm and are going to be full length sizing the cases (FL 8mm dies are made to the SAAMI 19 degree spec). The shoulder angle of the guages to be used depends on the ammo that will be fired in the weapon. Remember that the whole purpose of headspacing is to determine the "fit-up" of the cartridges that will be used to the chamber of the rifle. This is what determines the amount of case stretch that will occur during the firing phase (case stretch is what causes head separations). If you neck size the "fire formed" cases, headspace will no longer be an issue. The only concern will be during the initial fire forming stage itself.

 

[Ike27]

Bottom line.. Dont get too caught up on the head space thing. IMO military chambers and bolts are made to loose tolerances that modern rifles are not. Fire the rifle from the bench with a string and check the case.

Check the fired case and you will know the story.

BTW: Make sure you tear down that bolt!

 

[tm45]

You may have damaged that guage.
"When all else fails, read the instructions."

 

[travlin-man]

If it were me I would just chamber a round point in a safe direction turn my head and fire it.Then check the fired casing and if it looks ok I wouldn't worry about it. But I also have shot several hundred rounds of turk surplus thru a GEW88 after being told it would blow up.I guess I push the envelope but I've never headspaced or had headspaced any rifle I've ever owned I just use the above method and if it looks ok I just blaze away.But thats just me.


TM