Game Reaper 2 Signature Series two piece scope mounts fit long and short actions, some super short actions, left and right handed guns. Features machined from 6061 T6 aluminum, internal ring and base design allows for extra eye relief adjustment, reduces scope damage from tightening rings, no moving parts between the firearm and the scope, up to four times the threads of other mounts for absolute strength and security and absorbs shock and withstands temperature extremes better than steel mounts at a fraction of the weight. Base screws are 6-48 X 1/4 long. Ring screws are 6-40 X 5/8 long. Both use a 7/64 Allen wrench. Both mounts are not the same part. Back mount is taller than front mount because receiver is lower on back end.