I have been watching videos and the ak47 and AR15 seem to be pretty fast. But you can discern each round going off. The SKS on the other hand seems way faster. I had an sks and it went full auto on me 2 times due to dirtiness from ammo. 10 rounds sounded like BBZZT. I have seen full auto AR15 5.56 POP,POP,POP 3 rounds in about the time the SKS finished 10. Just stating things I notice.. I was looking on ways to increase rate of fire in the AR15 , I think I came up with lighter buffer and adjustable gas block.