Funny, I just got back and saw this response. For the full auto AK 47 shooting 7.62x39, I can pull the trigger as fast as that AK will shoot but for only 3 rounds before the AK beats it. Seems that way when standing there...no nanosecond clocks or high speed cameras here. Of course, that's with someone else on the AK trigger and me right next to him on the M4..I am not good enough to hold both simultaneously. Maybe Glockguy is a genius and can do that. I'll take that bet about 20 shots off from the AK before the 2nd round chambered. That M4 cycles FAST! My limited mental capacity only knows that my MP5 is much faster at cycling and rounds/minute than the AK. 1 round of buckshot at close range will stop the intruder regardless of cycle rate, rounds fired, mud in the barrel, relative humidity.
I don't do home defense with rifle or pistol because I care about my neighbors and family. The M4 will still stop the dude coming through with that auto AK before the rest of my family gets hurt. As far as dragging through the mud, the USMC has tested this for me and I learn from other's experiences, unlike some mental midgets.
Yes, I luv beating dead horses into glue.