Mosin Nagant piercing primers

A customer got a Mosin Nagant and surplus ammo (7.62x54R) He sent me an email and said:

The surplus ammo works perfectly in the rifle. My son wants to use the rifle this fall for deer, so we purchased some Winchester deer rounds for it. The primers on the original ammo are set slightly below the surface of the brass, while the Winchester's primers are flush with the end of the shell, which is causing the firing pin to pierce the primer casing altogether. While this hasn't seemed to hurt the firing pin or bolt (yet, after using half a box of ammo), the little pieces of brass from the primer are getting blown back into the bolt and jamming the pin mechanism, which 1) must be bad, and 2) is inconvenient since the bolt must be disassembled to unjam.

I told him the surplus ammo probably has a pretty hard cup and the firing pin spring is probably very strong to make sure, in a war time scenario the rounds are reliably ignited. I said the Winchester primer cups, as compared to the surplus ammo primer cups are probably quite a bit softer, thus the strong firing pin spring is piercing them. I told him he could try other none surplus ammo to see what happens, possibly find a firing pin spring that is just a bit weaker or just use the surplus ammo to hunt with (have to check what the bullet make up is and what the game laws say).

Any other ideas, remarks, suggestions. Both he and the son like the Mosin and according to him it is very accurate.

Can't you adjust the firing pin on a mosin with the often included headspacing gauge?

-Zach

Virtually all surplus 7.62x54R has FMJ Steel Core projectiles. Not good for hunting.
I have shot plenty of Herter's soft points from Cabela's and reload them with CCI or Remington primers. I've never seen a pierced primer.

I would try backing the firing pin out a bit. If there is a downside to this idea from a gunsmith standpoint, I am not aware, so let me know.

Ron:

^^^ What the others have said, the Mosin-Nagant FP can be adjusted for projection using the notches on the side of the teardrop-shaped screwdriver usually found in the accessory kit or inexpensively on-line. There are four notches, the two outer notches are just clearance notches for the rim on the boltface; the other two notches are the min and max FP projection gauge limits. Have him set it to the low end of range, and crank it out a turn at at time if it misfires for lack of protrusion.

YouTube instructions:







HTH,

Noah

Thanks for the replies, it looks like adjusting the FP will solve the problem. I'll send him the You Tube videos but he'll probably bring it in to me so I'll have to get one of the tools.