A friend had one on his AR15, bought it from a local gunstore here. The rear scope ring locked the focus ring right up tight! He had to loosen it to the point it was almost not even clamped on in order to allow the focus ring to work, and it still would stick.
He returned the scope, and the dealer has also since quite stocking them because the return rate was enormous. I have never heard a good thing about these scopes, nor would I ever buy one. The glass is the worst I've ever looked through to top that off. Simmons, Tasco and Bushnell are leaps ahead of this outfit! BSA is the only other scope I wouldn't have any part of, that's another story...