My friend cam over this weekend with a large batch of 7x57 brass that his father did not need any more. It is Norma Brass and I would like to use it to make .257 Roberts and then fire form to Ackley. What is the best way to get it down to .257. I have tried with a few cases but they seem to come off center. Thanks for any help.

With an old 7x57mm Wilson vise die, I can change 8mm brass to 7mm brass.

With an old 257 Roberts Wilson vise die, I can change that newly made 7mm brass to 257 Roberts brass.

With my rifle, I can fire form that brass to 257 Roberts Ackley Improved.

I have lots of 257 Roberts Ackley improved brass that says "8mm" on the headstamp.

It does not have too thick a neck, and shoots accurately.
Works fine.

love

Just use a FL 257 Roberts die. Size a little and test, size a little more and test, keep doing that until the case will chamber with a crush fit. Then fireform with a high end 257R load. Any crookedness will straighten out with the fire-forming.

Good Luck

Ray

Love22Hunt,
If you have not already reformed that brass I have some .257 that we might make a swap on.