I can not find any 6mm Rem brass and have just finished the parts gathering phase for a 6mm AI project. I do have several hundred 270 Win cases.
My plan is to anneal the 270 brass, push the shoulder back with a 7x57 die, neck down in a 6.5 Roberts die, then a 257 AI die then a 6 AI die. I realize that it will still require fireforming, but what other problems am I going to run into? I'm guessing that I will have to turn the outside of the necks also. Should I anneal again after all of the steps or fireform then anneal?