most any semi-auto can fire full auto if you utilize the bump fire technique. You allow the recoil of the weapon to “bump” the trigger repeatedly inducinga high rate of fire. There’s tons of videos on Youtube show how it is done. It’s bad ass but pointless IMO, real rifleman fire semi-auto.
Although, I'm fairly certain that BATFE regs state that the belt-loop would become a part of an "unregistered" machine gun while doing so.
I sh*t you not. They once ruled that a shoestring wrapped around the grip of an M1 would be a "conversion device" producing a machine gun.
"Real" riflemen know that suppressive fire has it's place, but "one shot, one kill" is still a mantra that works wonders.