A good way is first shoot "0" rings top and bottom...lets just say your pretty much straight with bore and scope...but 6" low and to the left 4". Try A -20 in front and A +20 in rear...these are on bottom of ring.Just put "0" ring shims on top. In an air rifle you can normally hold the scope down enough to get a shot off,try three shots. This just canted the scope downward towards your bullet hole on target. Now if your 8" low ...2" below the first shots at "o" rings, Put a -10 in front ring on bottom ,"o" on top and shot again. Almost dead on lets say but to the left 4" still, so cant the front ring up the left side of ring maybe 1/8" and rear ring cant up right side 1/8" snap in the "0 rings, you just canted the scope a little to the left , hold scope and pop a shot( this is an air rifle) Hopefully you now swung the scope to the left enough to cut the distance down to maybe two " or less.
Anyway that is how you move your scope to match the bullet hole. I ended up buying the gunsmith box of Signature ring inserts years ago. I think 10 of each. -5,+5,-10,+10,-20,+20. To do Daves gun the other day we played with combo's till we got it within an inch or so to the bullet hole. Since the scope is centered with cross hair( lets say turret travel 4 full turns to bottom out...go back two full turns, crosshair in center in glass,both elavation and horizontal) I also use very fine teflon tape and will build up under an insert to get it dead nut on...mostly for the 1K guns. This works best on the wider XTR scope ring set. You might be didling along for a good hour or more but you will slowly get it as close as you can with the different shims provided. Hope I didnt bore you, and hopefully got you where you need to go. AND no scratches on yout scope tube !!! LOL Pete in Montana