Even the Army, (My alma mater) has one listed as primary, infantry rifleman. We, even in the ordnance corp, had our weapon at the ready at all times in the combat zone. You could be called at any time to go to an infantry platoon and do grunt duty, fortunately I escaped that dillema, but it was a threat the non-coms and officers always held over your head. Whenever going on a field excursion, you always had your weapon in hand, and yeah, I did experience incoming more than once. The sound of an AK being fired at you is rather terrifying, the noise a round makes going by you is something one never forgets, generally, you hear the round before you hear the gunfire, like zing-pow, sounds like chinese food, eh? Incoming mortar rounds are even more terrifying. I would have made a terrible grunt.