Are you handloading the AAs? Will RGL's fit? If you aren't a high volume shooter, rather than remove metal in the gun you can't put back, consider chucking an AA into a drill and make a few passes on a stone. In order to hold the shell, find a short dowel that will snugly fit the inside of the AA. Drill a center hole axially through the dowel and run a 1/4" bolt down the center with enough out of the drill end to be able to be chucked. You may have to tape or hose clamp the hull to prevent the dowel from spinning inside the hull. Or swap the AAs for Cheddies or RGLs if they fit. Gil
