I'm gonna stop you right there, you just said an AR-15 is a high-powered rifle. It is obvious you don't know anything about guns and I shall ignore anything you say from this point on.
That and the fixed barrel. It does get rather warm after about 50 rounds. Also firing sequence does not matter. 1)Squeeze grip cocker, pull trigger; 2)Pull trigger and hold, squeeze grip cocker for each round; 3)Pull both at same time...goes bang each time.
We cannot play innocents abroad in a world that is not innocent. -Ronald Reagan