Excessive headspace

[CE310QT]

Ive just heard from the gunsmith about 3 rifles I was having him check.

2x Argentine 1891 Mausers both excessive by about twenty thousandths

Krag 1898 excessive by fifteen thousandths.

The krag is rimmed so I understand headspace isn’t as critical. He checked the argentines using cartridge plus shims since no one seems to make gauges.

Can Krag headspace be solved by new bolt?

I have no idea what to about the argentines.
I don’t reload but looks like I’m going to have to start and fire form cases.

 

[LoonWulf]

I THINK the easiest corrective action on the rifles would be to have the barrels on all set back one turn and reamed to the correct headspace.

The easy option would be to form cases to the chambers, as you are already considering, via handloading.

 

[243winxb]

He checked the argentines using cartridge plus shims since no one seems to make gauges.

Using a factory round and shims tell you nothing.

How can one set the barrels back without the correct gauges? You cant.

Order some. http://pacifictoolandgauge.com/cip-...x-53-arg-cip-headspace-gauge-set-min-max.html

 

[Bushpilot]

Can Krag headspace be solved by new bolt?

It could if you had a pile of Krag bolts and a head space gauge to try them all out with, otherwise you might end up with a bolt that gives you more head space then what you already have.... and it probably isn't going to cycle as smooth with an off the shelf replacement bolt....

I THINK the easiest corrective action on the rifles would be to have the barrels on all set back one turn and reamed to the correct headspace.

Yeah, that is the correct way but might not be financially worth it...

 

[Bushpilot]

He checked the argentines using cartridge plus shims since no one seems to make gauges.

Who says no one makes the gauges??? You can buy or rent....

http://pacifictoolandgauge.com/cip-...x-53-arg-cip-headspace-gauge-set-min-max.html


http://pacifictoolandgauge.com/saam...-saami-30-40-krag-saami-headspace-gauges.html

https://www.amazon.com/Headspace-Gauge-30-40-Krag-NO/dp/B00703MGEI

https://www.reamerrentals.com/ProductDetails.asp?ProductCode=30-40Kr.g

 

[Varminterror]

Using a factory round and shims tell you nothing.

It tells you if a rim-headspacing rifle has excessive headspace... such as the case in this thread...

 

[243winxb]

It tells you if a rim-headspacing rifle has excessive headspace... such as the case in this thread...

argentines

 

[243winxb]

argentines- buy factory ammo. Measure head to datum. Fire rifle using a pull cord. Measure fire cartridge. Note difference. Check for possible case separation. None? Reload brass using a neck size die. Fire and measure again.

 

[illinoisburt]

When headspace is bad, most likely it is from worn or peened lugs on the bolt. Yes you can have the barrel turned and reamed. Other option is new bolt fitted or a good tig welder can add steel to the lugs and machine back to correct tolerences.

New bolt bodies aren't too terribly expensive.

http://www.ssporters.com/product-p/1363-27.htm

 

[illinoisburt]

Can apply the same bolt rebuild with the Krag. Get a new bolt body and have it fitted.

https://www.granpasgunparts.com/1898-krag/1898-to-1903-krag-bolt-body

 

[243winxb]

2x Argentine 1891 Mausers both excessive by about twenty thousandths

Did the "gunsmith" switch the bolts between the 2 of them, to see if it made a difference in chamber headspace?

 

[Vern Humphrey]

Ive just heard from the gunsmith about 3 rifles I was having him check.

2x Argentine 1891 Mausers both excessive by about twenty thousandths

Krag 1898 excessive by fifteen thousandths.

The krag is rimmed so I understand headspace isn’t as critical. He checked the argentines using cartridge plus shims since no one seems to make gauges.

Being rimmed doesn't matter -- what he is saying is the case can back out of the chamber by .015". That might be enough to leave the case wall unsupported, allowing it to blow out and wreck the gun.

Can Krag headspace be solved by new bolt?

Yes and possibly. A properly fitted bolt would solve the problem, but first you have to FIND the proper bolt.

I have no idea what to about the argentines.
I don’t reload but looks like I’m going to have to start and fire form cases.

Fire forming can help, BUT if the case can back out of the chamber far enough to leave the case wall unsupported, fire forming will not solve that problem.

Question -- what does your gunsmith say about "fixing" these rifles?

 

[Scooter22]

Shooting a gun with "too much headspace" will allow the case to be pushed forward away from the support of the bolt face from the firing pin strike. Then the case stretched back under pressure the the bolt face thinning the web of the case. This can cause head separation in as few as one firing if very excessive.You can do two different things to take up the headspace issue and be ok ONLY if you are going to reload your ammo and NECK SIZE. With the 30-40 rimmed case slip a thin O ring on the case in front of the rim and shoot. This will hold the base of the case against the bolt face and allow it to fire form to the chamber. Then ONLY neck size. This is common practice for .303 Brit shooters.
For the rimless Argentines load your ammo so the bullet JUST touches the rifling in the throat. This will hold the head against the bolt face and allow the case to fire form. Then ONLY neck size. If you do a search you will find plenty on these two methods to shoot a gun with generous headspace with no problem. Only you can be the judge using the info but I have done it with no problems with several milsurps and relaoaded cases 10 times or so with no thinning. But ONLY neck size. JMHO

 

[CE310QT]

Vern, for the Krag he suggested turning the barrel back and reaming...which seems cost prohibitive for the old rifle.

He mentioned fire-forming for the argentines but same thing the best fix would be turning the barrels back--not possible on the carbine but could work for the rifle.

 

[someguy2800]

For all of them I would inspect them carefully for bolt and reciever lug peening and cracks. I would load a mild starting load, lubricate the cases liberally with rcbs case lube, and shoot them to fireform the brass. Then I would measure the cases with a headspace comparitor like the Hornady set, and adjust my sizing die to push the shoulder back .002”-.004”, and enjoy.

Continue to monitor the headspace length of fired cases to monitor lug setback. Note it might take a couple firings to fully form the brass.

 

[boom boom]

Just a few observations that O/P may or may not find useful. First, it is easier and cheaper to get a new Krag barrel (see Criterion) to correct headspace issues rather than messing around with bolts unless you have a pile of them. It will probably shoot better as well. It does take a special action wrench--Numrich has them or did.

There are still a few New Old Stock Krag bolts around --Grandpa's Gun Parts still had a few a year ago and such.

Regarding the fireforming--one, the o-ring trick for Enfields is not to correct for bad headspace but to correct for overgenerous chambers. Enfields, even with correct headspace often overwork the brass on full length resizing. American Krags do not really handle escaped gas that well as the rim was designed to seal the chamber and keep the gases from a cartridge separation sealed in the chamber. Enfields do have the advantage as they do have chamber venting.

The 1891 Mauser is a bit more problematic as the rear of the case is unsupported. However, Dave Manson, of Manson's Reamers indicates that SAAMI and the old military specification for Mauser 7.65x53 Argentine is off by .020". https://mansonreamers.files.wordpress.com/2015/06/argentine-headspacing-information.pdf That is why he refuses to make headspace gages for it. There is a similar issue in 8x57 Mauser where the older specification has a different shoulder reads differently off of a headspace gage calibrated to the new SAAMI spec.