Finally got my upper. I put together an ar15 pistol in 9mm. Its got a 4.5 inch barrel and a kak blade arm brace. Mounted a sig sauer romeo 5 on it. this little thing is beyond cool. Ive put over 500 rounds through it so far and it hasn't missed a beat. Only problem is I though all 9s used a 1/2x28 thread and this one has a 1/2x36 so I had to order an adapter for my suppressor so I haven't been able to try that yet. haven put it on paper yet either. My range is still snowed in. Sighted it in on a soda can on the snow bank behind the barn. So I don't know if its accurate yet either but it sure seems to be. at least at the 25 yards I was shooting anyway. Ive got a full sized cmmg 9mm AR too and always said it was the most fun gun in the same. I can shoot 5 or 6 handloaded 9s at the same cost as 1 5.56 reloaded with ball bullets and recoil is about identical. About as much fun as you can have with your pants on!!!!