I was a Tank / Leo 1 driver in Afghanistan, and was also issued a Browning HP. Mine was built in '47 i think and the pistol wasn't the problem, it was always the magazines. The followers would always stick at the bottom when loaded, and the rounds literally could fall out of the mag when inverted. I tried everything to get them to work, only put in 10 rounds, tried oiling, tried not oiling, tried dry lube, even tried stretching to mag spring for more power. Nothing would work.
It always fired the round in the chamber perfect, and i guess you only need one if the tank caught on fire.
Thats the way I saw it. Had a C-8 for an actual small arms firefight, and I always had my pistol with me inside the tank.