Well, I thought about it for a bit, and decided to try the .020 shim under the rear of the scope mount. Got it installed, and headed out to the range with a .012 shim also. I set the vertical range dial of the scope to midpoint, set up a target at 25 yds., and let go. Right on. Moved out to 100 yds., and fired another group of three and adjusted the scoe a little. Cleaned the barrel and fired the next group of five on a clean target. Still getting particles when cleaning. This group and all previous shots are with factory 300 gr. ammo (Rem). Looks like we've got a keeper...... Hope the handloads work up as well.