Mas 36/51 and Cartridge Bloating

[Illuminate]

I am a proud owner of a beautiful Mas 36-51. I bought it a bit overpriced (as I did my Mosin Nagant), but other than that it's great. It plinks minute-of-pie-plate at 100 yards, and I imagine it could do better if I did some serious bench-rest work.

Unfortunately, the ammo is fairly expensive - not what I'm used to paying for milsurps, at least. It runs 13.50 per 20 where I buy them. Being that ammo is said to be reloadable on the box, I decided I was going to go an (tediously, I might add) collect all my spent cartridges and put them back in their box to keep for once I get a reloading press and/or sell them on Ebay/Gunbroker/THR. However, every cartridge that my rifle has fired has a noticable (and by that I mean you can actually feel it by running your finger across the cartridge) dent near the rear of the casing. The dent is about 1/4 of an inch from the rim. Is this ammo still reloadable?

 

[foghornl]

'Dent', as in toward the center of the case, or 'bulge' as in protruding outward from the case? ?

If it is a 'bulge', you could have a bad chamber or a headspace problem.

If it is a 'dent', your brass may be hitting something on the way out.

Not even having seen any of the MAS rifles, I can't really say anything more.

 

[Illuminate]

Buldge. Is fixing a headspace problem difficult?

 

[Jim K]

Case bulging is not usually due to excess headspace; it is due to a chamber that is oversize in diameter or ammo that is undersize.

What ammo are you using? I know of no 7.5 French ammo that is reloadable in the normal way; it is all Berdan primed. Check the headstamp; it may have been made up from some other cartridge. Some folks have been making that case out of .30-'06, which has a smaller diameter head and will bulge in the 7.5 chamber.

Also, some of those guns are in the original French 7.5 while others were reworked to 7.62 NATO (7.62x51 or .308 Winchester).

In any case, bulged cases limit the case life if they are full length resized at each loading. You might be able to neck size only.

Jim

 

[Illuminate]

Well, it's new-production stuff. Portuguese. Says it's Boxer primed right on the box, and its headstamp says "7.5 MAS". It's not been converted - All the markings say 7.5, and I don't think they converted any Mas 36s - Just 49s.

 

[AC]

Illuminate, How much of a problem this is depends on the degree of bulge.

Case specs for the 7.5 French (and 6.5 Swede) show a larger base diameter than the cases based on the 7x57, .308, and .30-06. Unfortunately U. S. manufacturers of the 6.5x55, a case from which 7.5 French can be easily made, chose to use the smaller diameter. It is possible the Portugese brass does too, though I have no personal knowledge of that. This size discrepancy is why I bought Lapua cases in 6.5 Swede to make my 7.5 French cases from, they are larger in the base.

But having gone to all that trouble there is still some bulging of cases fired in my 7.5 Mas semiauto. I'm not worrying about it, but you can't see my cases and I can't see yours.

When you start handloading it would be wise to only partially size your cases anyway. They will then retain some of that bulge and will last longer.

Yes, your cases can still be reloaded.