Mystery brass

C

Camaroguy

CGN Regular
Rating - 100%
7   0   0
Location
Manitoba
Found a bunch of these at the range. Anyone know what caliber these are? First picture is with a 30-06 on the left, and a 308 on the right. A 308 bullet will not quite slide into the neck. It is berdan primed.


 
AlbertaJohn is correct; it's 7.5x55mm Swiss
Gewehrpatrone 1911 (GP11) made in 1982

Quite a bit of it on the market still. Several people around CGN reload it and the correct size berdan primers are available from Budget Shooter Supply (though he's going on summer holidays). It is sort-of convertible to boxer primer (small or large depending on technique) and I'm having a go at it but if it doesn't work out I'll just buy some Prvi brass.

It can be loaded with .308" bullets but the earlier GP90 I believe was loaded with a .306" bullet. The GP11 is fully non-corrosive.
 
Last edited:
GP11 on the left, my neck sized loads on the right. You can see how much the case blows out to fill the chamber.
 
Hitzy said:
GP11 on the left, my neck sized loads on the right. You can see how much the case blows out to fill the chamber.
Click to expand...
As far as I've read it appears there are two sets of chamber dimensions for the 7.5x55mm cartridge. The K31 has the larger chamber at the shoulder and the older rifles (from 1890?) had a smaller chamber. It's a much greater difference than most tolerance ranges, even for a surplus rifle, and the K31 chamber can be .015"+ larger at the shoulder. Most dies are designed for the smaller size so they work in all rifles but Redding does make a sizing die specifically for the K31's larger chamber. I ordered a set of Lee dies, including a neck sizing die, but I'll most likely be ordering the Redding die eventually.
 
You must log in or register to reply here.
Back
Top Bottom