Drags made a very good point. If you do shim up the rear base you will have two rings that are on different planes. This would require the rings to be adequately lapped to avoid scope tube distortion.
The Burris Signature rings are designed to automatically compensate for the thicker insert placed in ANY location. No lapping required.
NO, the Burris inserts can not be used in ANY rings, they are curved on the exterior side and are designed specifically for the Burris Signature rings. Check out the "Posi-align offset inserts" near the bottom of this page. http://www.burriscompany.com/rings.html
[ 02-15-2004: Message edited by: Varmint Hunter ]