Shot Shell Problem

[Gabriel Law]

A friend of mine has a 'new to him' double twelve gauge.  At a recent event, he borrowed some of my ammo, and on the very first round he fired out of the gun, the primer back up and was pierced by the firing pin.   This ammo works fine in four of my own guns without issue....AA Winchester hulls, fibre wads, 2 3/4 drams FFg GOEX, and 1 1/16 oz #8's.  What zup???

[Gabriel Law]

I solved the problem.  The firing pins are integral with the internal hammers, and were rough with sharp corners, and protruded more than necessary through the standing breech block.  So, having disassembled the gun, I rounded the pins and polished them, and re-assembled the gun.  I loaded some reduced loads:  65 gr. FFg Cartridge GOEX, normal over powder, fibre filler wads, 7/8 oz # 7 1/2's and a thin paper over shot wad prior to crimp.  I use the over shot disc to prevent shot loss through the crimp.  Yesterday, I tested the gun, and it performed perfectly...happy camper!  So I shot two of my own hotter loads:  same but for 75 gr. powder and 1 1/16 oz shot, and again, no issues at all.  It's wonderful and satisfying when things come back around successfully.