text: Add 2 sets of gas rings and an enhanced firing pin (7.62x39 firing pin) to the AR kit. I've seen firing pins bent and gas rings take the brunt of the wear in the BCG. The reason for the enhanced firing pin is that they are about .005 of an inch longer and in the case you could never buy ammo again and where to run across a cache if hand loads that where primed with hard primers the enhanced firing pin will run with hard primed rounds. A standard milspec pin will not, it does not penetrate deep enough to get reliable ignition. A few years ago I bought bulk 223 that was primed with hard primers inadvertently and they where selling it for 75$ per 1000 but they noted you had to switch your firing pin. I bought several thousand rounds and used them for training ammo. Had about 14-15 misfires in 2 mags with regular pin and and zero with the enhanced pin. I still run that firing pin and no issues with a couple thousand rounds of standard ammo.