am looking for some advice I have the Tikka tac A3 S&B 5x25x56 , I have just put my first rounds through it but I have a small problem. I spuhr mounts with 20 mod as you suggested. After spending time at the range trying to zero the gun in but when the crosshairs are on the bull the shot is high and I don’t have any more travel on the. Elevation turret so my question is will I need to shim the back by a 0002 of an inch or will it mean buying new flat mounts , any other advice I would be grateful