DNZ's Game Reaper is precision machined from a solid block of top-grade billet aluminum, and is custom made to fit each type of firearm and align perfectly with your rifle receiver with no moving parts between the firearm and the scope. The Game Reaper absorbs shock and withstands temperature extremes better than steel mounts. This mount will not fit 2008 and older models. Check hole spacing dimensions below if you have an older model. Base screws are 6-48 X 1/4 long and ring screws are 6-40 X 5/8 long. Both screws use 7/64 Allen wrench.