I am sure that everyone has chimed in on the good, bad and the ugly of gas pistons on AR's so I am going to stay away from that. But I did want to report on my experience with one of them. I installed an Osprey 416 by Osprey Defense out of Florida. All I can tell u is the system works fantastic. Install was smooth and simple. It does require a fore grip that has enough room for the piston. I bought their quad rail and it is excellent. Workmanship on both items was impeccable. If u are considering buying a gas piston take a look at theirs. You won't be disappointed.