User blog comment:Griever0311/Ask A Marine/@comment-1260687-20100317141153

@DJRosetta: Everyone uses the M9 as a standard sidearm; (@Slowrider7: Air Force personnel hardly ever use a weapon; when they're issued something, it's usually an M4 or M16). I'm most experienced with the M16A4; I was trained on it since boot camp, received four "expert" grade qualifications on it, and carried it as my primary weapon for the majority of my service.