Old ammo - Still Good?

[AMProducts]

The rifle has a generously long chamber and factory ammo is made to minimum chamber size, slightly less for the cartridges that I measured. As a result new factory brass grows about 0.014" on being fired. Dry brass will hold to the chamber walls and the growth will happen in the head area. Oiled brass will slide back against the bolt face before pressures increase enough to cause it to hold to the chamber walls, causing the growth to happen in the neck area.

I threw out over 100 pieces of brass that had case head thinning, many of them once fired (by me) factory cartridges. Of the 10 or so that I oiled before firing none of them show any signs of case head thinning. Reloads of this brass won't need to be oiled.

It goes to show that oil on your brass isn't necessarily a bad thing and I wouldn't hesitate to use a very tiny amount to stop corrosion.

That doesn't strike me as "safer" that sounds like excessive head space to me.

 

[U201491]

The rifle has a generously long chamber and factory ammo is made to minimum chamber size, slightly less for the cartridges that I measured. As a result new factory brass grows about 0.014" on being fired. Dry brass will hold to the chamber walls and the growth will happen in the head area. Oiled brass will slide back against the bolt face before pressures increase enough to cause it to hold to the chamber walls, causing the growth to happen in the neck area.

I threw out over 100 pieces of brass that had case head thinning, many of them once fired (by me) factory cartridges. Of the 10 or so that I oiled before firing none of them show any signs of case head thinning. Reloads of this brass won't need to be oiled.

It goes to show that oil on your brass isn't necessarily a bad thing and I wouldn't hesitate to use a very tiny amount to stop corrosion.

Its best you do that with mild loads then and then once fired shoot dry on future reloadings, but better yet go to a gunsmith and have that chamber cut back and sized right or at least have it gaged and checked.
Oiled cases put too much added pressure on your bolt face and lugs. Admitted not a great deal but enough to be too much in time.

 

[Steve M]

Think of it as fire forming brass to a wildcat chamber, it only gets done once per case and on new brass only. Yes, it is excessive headspace because of modern ammo that is made to a specification that didn't exist in the 19th century. It would be less costly to buy another rifle than to have the barrel set back and the chamber reamed.

I didn't dream this up on my own, it is a legit fireforming technique as described by John Barsness:
If the headspace is a little long but cases will still fire consistently, oiling the case will allow it to slip rearward without stretching. No, this doesn't increase bolt-thrust. Any suitable oil loses its lubricity at pressures below 10,000 psi. Once pressure rises to 10,000 psi, the case grips the chamber wall firmly.

This technique was on factory loads, on handloads in new brass I would do this:
The solution is to seat the bullets into the lands, keeping the case head firmly against the bolt face. Bullets seated into the lands increase pressures, so a starting load for the parent case should be used. This is also a handy technique for fireforming brass to the generous chambers of some old military rifles.
http://gunsmagazine.com/fireforming-brass/
This doesn't help the OP with his issue except to challenge the theory that a little oil on the brass is bad juju.

 

[DeanMk]

Was the "generous headspace" issue solved with the 95 Mauser?
I've been shooting my brother's Chilean 95 since I can remember and don't recall seeing anything "odd" with fired cases from that gun, but .014" might not be enough to see with the naked eye.
I don't reload, as I have plenty of ammo for this gun and (I think) this is the first I've ever heard about oiling brass for these fine old guns.


Dean

 

[Michael]

I had a few boxes of .38 SPL LRN from about 1986 that I forgot under the seat of a Blazer that frequently had its top off (getting very wet under there). The boxes disintegrated when I tried to pick them up in 2004, but they all fired just fine.

 

[U201491]

Was given several boxes of 12 gauge, .22, 270 and .38 and was wondering since this has been kept in dry atmosphere, but is maybe 20 years old, is it still considered safe to fire?

99.999% yes if it has been stored as you say. I have used ammo from over 50 years ago and it performed fine. Some that was actually from the 1920.s maybe earlier. And a lot of 1940's ammo.

 

[DeanMk]

Here's a video I posted in another thread I started yesterday, but it applies here as well....

...notice how old he says the ammo is, then notice how well it works!



Dean