Learned more than a few things about scope mounts for an M77 with a tang safety this week. Numerous scope mount cross references tell you that Remington 700 scope mounts will work on the M77. This is only half true. The screw holes have the same spacing but the mount heights are not the same. Weaver makes the correct rear mount for the M77 but sadly it's aluminum not steel. Warne made one but it's unobtanium unless you find it on Ebay or in a junk box somewhere. The fix I found is to use Burris Signature Series rings with the Burris 1" Signature Ring Pos-Align Offset Inserts to compensate for the mounts. Using the inserts, I should be to zero the scope correctly.