"my m14 is using a 50mm buck scope, and this holds it fine. you can still use the iron sights just fine under it, i shoot through the iron sights under it constantly. it mounts onto the side, and requires a little bit of tooling to put on the screw in points, but its sturdy as a brick and will never fall off. never had a paint issue, never had any issues at all. quite heavy, and easily removed, and put back on. after you put in the screw in mounts, you can simply remove and attach it with just the two large screws. can hold just about any optic you can find."