I have them on several guns. Both with Leupold and Burris scopes. They work really well. As always, you need to make sure of altitude, temperature and all the other details that go into the calculations. I walked thru the calcs with these guys and compared to my Sierra Infinity software and we were within .25 inches all the way out to 1200 yards. Good enough for me. We have also tested them out to 1000 yards and they work very well.