I have a 3-9X40 Buckmaster on a Rem Sendero 338UltraMag and it has over 100 rounds since mounted without loss of zero or any other failure and this was after it came off of a 7mmSTW. They hold their zero better than any scope I have used including Leupold, and I am not knocking Leupolds, I just think the Nikons are terrific.