Best "Black Rifle" on the market today for the price, this rifle uses a short stroke piston that beats any AR-15 rifle hands down that just uses the very small gas tube, and the piston does not allow any gases to flow back into the bolt or bolt carrier. Great rifle all around, lots of 1913 rails to hang things on, even has a setting on the gas system that allows the rifle to continue to be fired even if it is too dirty. The rifle is a bit heavier that the AR-15 rifle, but this is only a problem to a small female. The fit and function of this rifle like all Sig weapons can not be faulted. Really all I have to say to show my satisfaction is that this is my third Sig 556, and I love them.

Low recoil, seems accurate, and fun to shoot with red dot site. Has multiple malfunctions when magazine not inserted completely into gun, or when hand bumped plastic magazine while firing. Will see how gun does after 500 rounds, as this testing was done on new gun with 30 rounds. PNC ammo may be problem, but again I will check after a few more rounds. Nicely balanced, expensive, and the ejected shells mar the finish by the ejection port. I hope this does not translate into a rusting problem later.