I bought one of these for my AR-10 so I could use it to rifle hunt this year. It basically turns your semi auto into a bolt action. It's a little hard to rack the bolt but other than that it works pretty good. I might experiment with a lighter buffer spring so it's a little easier to cycle. The only issue I had with it was the new charging handle hit the frame before the seated all the way. I had to take off about 1/8 in to get it to function properly. It didn't effect the zero at all.