Chilean Mauser: 8mm or 7mm?

[XLesky]

Thankyou everyone for your responses. Had a good look at the rifle yesterday, it was made by Loewe and according to what I could dig up on the net means it was built in either 1895 or 1896 (all Chileans were made by DWM after January 1897).

As I said, there is no evidence if modification to this rifle at all. The bolt, action and barrel all match so I would believe it is still 7x57.

One more question: being a 105 year-old rifle, how would I ascertain it is still safe to shoot?

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[Patrick Chadwick]

One more question: being a 105 year-old rifle, how would I ascertain it is still safe to shoot?

Someone is bound to answer "take it to a gunsmith and have it checked out". But while this advice is safe - if the gunsmith knows anything about old service rifles - it is not very helpful. I (and many others) shoot regularly, and in competition, rifles that the average gunsmith who does not understand these old bangers would not be able to confirm as being safe to shoot. Why not? Because by asking that question of a professional person you are implicitly holding him liable for the answer. So his only safe position has to be - condemn, and thus avoid any question of liability. You pay him his fee, and are subsequently none the wiser...

This is one case where you must have (or rapidly develop) a bit of know-how yourself, and take some responsibility. No-one in this litigious world is going to say it is safe to shoot. That will, ultimately, be your decision. The question has to be turned around - "how would I ascertain it is unsafe to shoot?".
There are a couple of obvious points, and at least one that is not so obvious.

1) Obstructions in the bore.
No joke. A couple of percent of bore restriction can be sufficient to cause ringing - or worse.

2) The slamfire test
Cock rifle on empty chamber. Bang butt hard down on wooden floor or plank. If it fires, it is dangerous.

3) The safety-off fire test
Cock rifle on empty chamber. Put on safety catch. Pull trigger. Rifle must not fire. Release trigger. Put safety to "off".
If the rifle now fires, it is dangerous.

4) Firing pin (a.k.a. striker) tip
Inspect under watchmaker's eyeglass tip must be rounded, not jagged or sharp-edged. Badly shaped tips may pierce the primer.

5) Bolt end play.
Cock the rifle on a chamber loaded with a dummy cartridge (no primer!). The bolt is tight in the action body. because of the firing spring. End play appears to be very low or zero. Now fire the rifle (or release the firing pin in a controlled manner). Check the end play. Firing pin tension has been removed, and the bolt will have some end play. It cannot be zero, otherwise the bolt could bind, but should be much smaller than an acceptable head clearance, otherwise the bolt lugs will really be taking a beating. In bad cases (I had one) the rifle will not reliably fire a live case, because the combination of bolt flying forwards when the sear is released, shoving the cartridge forwards as far as the headspace will allow, and then rebounding back onto the lugs, may mean that the firing pin is unable to detonate the primer. The locking lugs may be already so deformed that the rifle (or at least the bolt assembly) is useless.

6) Dangerous (not cosmetic) rust pitting
For this, you MUST remove the barreled action from the stock. The worst pitting is usually below the "waterline", where it remains unseen and growing for decades.
Use a dentist's pick or needle to dig down into any pits on the barrel or action body.

7) Cracks in the action body
Unless you have access to ultrasonic testing gear, the simple method is to wipe over the clean action body with a highly volatile liquid, such as acetone. As the liquid evaporates, it will remain longest in any cracks, which will therefore show up as a dark line for a few seconds.

8) Splits in the neck (it's no fun if the rifle folds up on you when you fire it).
Place the neck of the stock on your knee, and press down with your hands to flex the stock at the neck. If you see any cracks, leav the gun unless you know how to fix it/are prepeared to have it properly fixed.

9) Wrong chambering (i.e. the marking on the rifle - if any - does not match the actual chambering).
ALWAYS check the actual chambering on ANY old rifle.

Please note: you can conduct all the above tests yourself.

What have I not listed? - Headspace! The chances are high that if you take your rifle to a gunsmith who is not milsurp-savvy, he will stick in a SAAMI headspace gauge, see that the chamber swallows a NO GO gauge, and say the rifle is dangerous because of excessive headspace. I would like to be given all old service rifles that have been condemned in this way - I could get rich on the sizeable fraction that are perfectly good shooters.
In general, you can expect a huge number of non-US made service rifles to fail when tested with SAAMI gauges. The topic flares up again and again, especially on Lee-Enfield forums. Basically, service rifles have generous chambers compared with modern CIP or SAAMI specifications. Really unacceptable headspace (for safety, not for case stretching) for an old service rifle is usually way beyond gauge limits.

Do the tests 1-9 yourself and decide. Nobody can give you a guarantee, so if you do not have the experience yourself, go through the tests with someone who does.

Patrick