15 thou. headspace on M1917... what to do?

[CouldBeWorse]

I bought a M1917 this spring at a local gun shop, and took it to a local smith for some minor work. The smith reported that he was unable to work on it, because it failed the 14 thou. 30-06 field gauge (he measured it at 15 thou.).

I'm wondering what my repair options are (and rough costs). My primary use is 200 yd. target shooting, no benches. I'm not a collector, but I do enjoy the history.

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[Patrick Chadwick]

I would not worry one minute about that. It's not a benchrest rifle. It's a very tough battle rifle.
And the M1917 has an extraordinarily powerful camming action. Unless he is familiar with these rifles, and closes the bolt very, very tenderly, it is quite possible that the gunsmith has actually compressed the gauge without realizing it.

I find 15 thou an acceptable value, if a bit higher than one would like, but then I always reload with necksized case that were first fired in the same rifle that is used for firing reloads. And I have seen 308 fired in a 30-06 and 30-06 rounds fired an an '03 that seems to have been rebarreled by Bubba with the barrel set out1/2 turn - yes, you read that correctly - 100 thou headspace. Ignition was unreliable, and the cases developed those bright stress rings near the base, but nothing split.

And an Arisaka with so much headspace (about 0.8mm) that ignition was erratic. After firing, the case shoulders weren't where SAAMI and CIP would like them, but the rifle told me (if I understood it correctly) "Japanese arsenals never heard of SAAMI".

Come on guys! We are talking about military rifles, made so that the user could drop a clip in the muck, wipe it on his battledress trousers, stick it in the rifle - and it was STILL expected to work. Enfields and most others did that. Ross rifles got the push from the troops when they couldn't take it.

DON'T FIRE HEADSPACE GAUGES. FIRE NECK-SIZED CASES FROM THE SAME RIFLE

Repair options - not required.
Costs - if you are a reloader, get yourself a neck-sizing die, or...
...Simply smear over the case shoulder with a felt-tip pen, set the full-size die back half a turn, and empirically resize and try the case in the chamber, moving the die up about a 1/16 of a turn at a time until the pen mark shows a bright line around the shoulder. Not just a speck of brightgness - you will get that from the skew of the case as it is chambered - but a reala line showing that the shoulder is making firm contact in the chamber. Then back off the die about 1/4 turn, clamp it, reload your cases and enjoy shooting the rifle.

[Chuckindenver]

i would find another gunsmith...have no idea what 15thou is..
buy a set of gauges and check it yourself.
not that hard to do...buy the tools and ill walk you through it.

[Patrick Chadwick]

...have no idea what 15thou is..

= 0.015 inches, or 0.001 inch more than "the 14 thou. 30-06 field gauge (he measured it at 15 thou.). In a rifle with a huge camming action.

If the gunsmith, for instance, didn't remove the firing spring before using the gauge, he will hardly have been able to feel the contact between bolt face and gauge.

Buy a set of gauges for a one-off measurement? I wouldn't. Always use necksized reloads for old rifles.

It really is nothing to get into a twitter about.

[jmoore]

My very first M1917 "failed" the "gunsmith's" headspace check way back in 1978 or 9. It's still shooting...

[Calif-Steve]

Most Gew98's will "fail" the headspace test. Most gunsmiths don't know how to check a M1917 headspace. I would make sure the bolt and receiver are from the same factory. Then I would stop thinking about it. Good luck.

[jmoore]

Most gunsmiths don't know how to check a M1917 headspace.

Quite right. It's easy to miss the slight incline of the locking lugs on this design. VERY slight. Gives about 100:1 leverage on turndown!

[Chuckindenver]

on rifles that cock on closing..felt resistance on the tool is pass, no resistance is fail. with cocking assembly removed.
no go, is 1.947 field reject is 1.950. i think your gunsmith was using .15 thou to impress you....
had he said...your rifle failed Feild reject..then id check a few things...

[CouldBeWorse]

I bought a Clymer field gage, and (with the firing pin and extractor removed) I can close the bolt without touching it: I just shake the rifle and the bolt handle drops. I saw the "shake test" done on a M1917 where the bolt didn't close.

I took some Winchester commercial rounds to the range, fired 3x, reloading lightly (Lee Classic loader, 125 gr Speer TNT, H4895 using Hodgdon's "Light Loads for Youth").

The casings and primers seem OK, but I'm new to this, so I don't really know what I'm talking about.

[CouldBeWorse]

If I neck-size only, should I trim to a non-standard length? In 3 firings, cases have stretched beyond max length.