Originally Posted by RLA
I have tried 200 AB's and they would not group at all.
Take a cleaning rod with a tight fitting patch.
Insert it a couple of inches. Mark a dot on the rod, and the end of the muzzle as an index point. Put additional dots on the rod at 1" intervals.
Slowly insert it, and count the inches to a full rotation.
Make sure it's a 1:10 vs a 1"11-1:12.