I just got the Black hole and have about 75-80 shots into it and I' m not sure how long it' ll hold up. They' re a breeze to remove though. I shoot the 125 magnus snuffers on a 400 gr 2312...big. They fly pretty near my FP but hit about 1-1 1/2" low @35. I use a slide type site though, so it' s a simple marking on the gaurd btw the two.