I put them on my Mossberg 930 after discovering that the gun patterned high (w/shot) with the stock rear sight at its lowest. No problem bringing the POI down, there is a lot of adjustment. As was mentioned the set screw when tightened firmly will distort the dovetail so make sure it's whre you want it before tightening securely. I don't know about the height on the M2 but on the Mossberg it works well. Durability wise I can't say yet, only one match on it and it didn't get smacked.