I was once an Air Force Security Policeman. I was at Kunsan AB Korea during the late ‘70s and my usual armament was both a .38 and 18 rounds and M16 with 240 rounds. My grenadier had M16 with M203 40mm grenade launcher with 240 and 40 rounds each. My machine gunner had an M60 with 2500 rounds. Drove around in a M706 or M113.
And in my previous assignment at Ubon RTAFB Thailand I was issued 480 rounds for the M16, until the last week before we closed down the place. We were then taken to the firing range, given an old rusty Vietnam War reject M16, and we shot up all the 5.56 ammo that was in the armory but one 20 round mag for each of us.