Re: 257 WBY resizing problem
The brass that keeps popping back try sizing then annealing then fl size should take care of the spring in the case. The other might try neck size about 2/3 back could be bumping shoulder and causing it to flare out like a flange. One time I had a 22-250 that I had to file the shell holder down to size it small enough to chamber. Just a guess good luck and let me know if this helps.