The current M-4 is a full auto, burst, or semi auto weapon. While I refuse to waste the tax stamp money on a full auto M-16, I can hit a gnats bellybutton easily at 300 meters with my AR-15 with PVS-14 scope fitted... day or night.
Grunherz, I have an MP5K, and that I do pay the tax stamp on. Firing it on full auto is just a waste, thats why 3 rounds is quite simply the best way to go. By the way, what did ya think of it?