Nice. What kind of rifle?
1/2” shift in scope mount is wild. First time shooting a scope, I typically have some blue tape to mark the eye relief when setting it up. Helps as a marker when shooting. Never had a scope move after mounting, but good to know if didn’t move in case need to troubleshoot anything.
.308 AR I built up. Barrel is the best part, an 18.5" Criterion that I recently shimmed to the receiver. It kicks, but not at all intolerable with an adjustable gas block to tame things. The flyers I used to get are gone, even with surplus 7.62mm ammo. Looking forward to next range session with some Federal Gold Medal Match ammo.
Scope movement was my goof. I had lapped the one piece Aero mount and the bare aluminum bothered me so it got a light coat of oil. Used a torque screwdriver, but did not bring it to check the tension after travel and temperature swings. Bought another torque screwdriver to leave here.
Whoops! Using lube on a joint meant not to slip.........Had too many little things turn out to be not locked down enough on this rifle, pride and hubris (thinking something did not matter) slowed my working through them all.
De-greased it all and put it back together. Be a while until I get back to this range, and will mark the scope as you mention, and have a proper height stool to get solid behind the gun. I believe the scope mount had lost screw tension over time. Will add that to pre-shooting checks from now on.
Attached an aerial view of the range I use.