My boats had .50 cals. You could have a side arm. Most chose a .45 acp, only revolvers I saw were pilots we pulled out of the rivers. Early M-16's were having issues at the time. M-14's were bulky in confined spaces (boat deck) so some of us chose an M-1/2. They weren't all in M-2 configuration. One guy had an M-3 like Dave. Said easier to obtain ammo. I didn't like the heavy bolt slamming. We took in ROK troops using WW2 weapons. No shortage of extra weapons available if you wanted something. Dave says stolen, some might say appropriated. You could also pick up extra (Wounded or KIA) weapons, either side. Guys coming out of the bush could have trophy items *#@ not always weapons. Some stuff got smuggled home, some caught at check points. Long time ago now.