Re: 30-378 reloading questions
I use a bushing die in a different caliber, I think it would be best to measure your fired cases and go from there. Brass will vary some, and it depends if you turn your necks. I think most people say 2 or 3 thou less than the outside of your fired case. I would suggest to have a few sizes so you can play with it a bit and see what it likes, switching bullets might make a difference too. A heavy recoiling gun may need some more tension as well.