[jdun]

I forgot to point this out.

Unless you're an Officer, the guy that is dragging the machinegun, MP, manning/operating vehicles (pilots, tankers, etc), SF, or isn't issued a rifle you won't be carrying a pistol.

Pistol are defensive weapons. In the military pistols are issue to personnel that needs a weapon to defend themselves. Machinegun like the SAW are heavy, hard to maneuver, and jam often. They are issue a pistol for personnel defense. Pistols are issues to pilots and tankers because there is no room to store the rifles in the vehicle.