As of 2000 (when I left the US army) a majority of the M16's were the M16A2 model which has the 3 round burst and semi-automatic mode. The older M16A1 model had full-auto and semi-auto mode. There were still a few around when I was getting out but they were being phasediout. I'm sure in the deer hunter they used the A1 model. They actually changed the full-auto mode to the3 round burst modebecause they found (in Vietnam) that the average soldier wasted loads of ammo in a fire-fight because they were terrified.