Awesome video..great job. Professional..really.
However, the cyclic rate of the M4A1 is to low, it shoots much faster than this.
I know being nit picky...but little details..well you know.
Watch this video..its an M16A2, for those that don't know..an M4A1 is a shorter barrel, collapsible stock equipped M16A2 that can shoot full auto vs. 3 round burst.