There has been some confusion with readers about the AR-15 that Hamfist uses, since it is the same designation as the AR-15 you can buy at your local gun shop. Back in 1969, it was a redesigned M-16.
The AR-15 issued to Forward Air Controllers (FACs) was identical to the standard-issue M-16 in function (single fire or fully automatic), but had a short collapsible stock that enabled it to be carried aboard the aircraft.