6BRinNZ: Nothing scientific or any hard and fast rules. When I see the number of times reloaded, could be as little as 18 or as many as 24, I may use the next smaller size bushing for a little more bullet pull, my thoughts being that the brass is at least a little more work hardened compared to when newer. With an even higher count, around 30 may even go for one size smaller again. Throughtout the whole range, I've never seen any changes in groups sizes, with the 6ppc's (4 chamberings) and the 6BR's ( 3 chamberings). "Heavies", thinking out loud: Tight fitted necks has to be a consideration. The ppc's are 2 at .272" chamber necks, loaded round neck dia. .270", sized with a .269" bushing = brass being worked a maximum of .003". The other 2 chamberings are .262" chamber necks, loaded round .260", bushing .259", for that .003" difference again. Two of the 6BR's are .265" chamber neck, loaded rounds at .263", bushing at .262". The brass just isn't going anywhere. In my .272" no turn 6BR, loaded round necks are .268"/.2685" with a .267" bushing, so still minimal brass movement. Gotta be the major reason I have no need for annealing. Factory chambers like my 222, 223, 22-250, 308, are used with Lapua and Winchester brass, bushing dies, so those necks are being worked more, but I'm getting 13 to 15 loadings before the occassional neck splits show up, and by then I feel I got my moneys worth out of the brass, so just toss it. The cost of replacement brass would be at least partially off-set by the expense of the annealing equipment, especially if going for one of the $400 units? Yes, I agree annealing can have its advantages and understand its benefits, it's just not for me/ too involved and I've gotten so much conflicting information when I question others about the proper way to do it, I don't want to get into it.