Before buying anything.. try taking say 100 of any headstamp you’d like, as long as they’re the same and load those and see if the variations get better. I had a friend that used mixed brass and his stuff was all over the place. I gave him a bunch of stuff I had, all same headstamp, but fully processed minus rollsized and he loaded it up and got a variation of +/- .003” vs the .010-.015 he was off before that… worth a shot and won’t cost you a dime…