To be honest, I really couldn't tell you, I don't know a whole lot about AR15s. Bought this from a friend a few years back and just added the sights, forend, grip, etc. It's a lot of fun to shoot, I just don't shoot it nearly as often as I had planned. Maybe took it out of the safe twice in the last 3 years.
Edit: I should probably add that my friend built this rifle. He put 1 magazine through it to make sure everything was in working order before I purchased it from him, then I put on the extras noted above.