I just mounted a leupold vx111 2.5-8x32 on my s&w performance center which has the 10.5" barrel. I had a tough time finding the right rings for the gun. I first started with mark 4 rings in med, and they were too low, objective was touching the barrel, then a customer service rep at leupold told me to use prw rings, then spoke to another rep and he said not to use prw's that they have had complaints with the 460. Then I called weigand, and they said they don't have rings to fit performance center mount, so tried warne maxima magnum steel high rings in silver and used 3 rings on it, 2 in back and 1 up front. Seems to be real tight, I haven't shot it yet, just mounted it tonight, I had a lgs mount and bore sight for me, he said it was a nice tight fit and should be good to go. Sorry for long post but I wanted to share my experience in finding the right rings. Hope this helps you, cause the only info I could find was to vague.