My upper finally arrived. This is meant to be a 3 gun trainer. The fit and finish is superb. I Have not begun accuracy testing on this upper receiver. I am in the middle of function testing. the performance and functionality of this upper receiver is amazing. It runs with most anything that I have run through it. I have fed it Winchester Super X, CCI, federal target, Remington thunderbolt and gemtech subsonic. I expect it to do the same with most anything else that I feed it. I ran around 300 rounds through it on the steel silhouette course today. Yes, that is a real partagas Lusitania and it was great.