Looking for advice and/or instruction on forming or neck sizing 25 BR Brass from 7mm BR brass

Thanks for help.

I am assuming you have a 25BR die.

It would be a easier to expand 6mm BR than to neck down 7mm.

If you have the 25BR die just run the 6 BR brass into it and expand the neck. Shoot it to fire form it and load as normal. Lightly lube the inside of the necks if you use this method.

If you use 7mm brass you may have to turn the necks. Lightly lube the necks and top of shoulder with Imperial sizing die wax. And run up into the 25 BR die slowly and with multiple short strokes. A little a time. If you see dents, there is too much lube on the brass. If they crush and deform then you will have to try stepping to 6.5 mm BR first.

If you dont have a 25BR die try putting a 25 caliber expander ball in a .308 maybe for the 6mm.
If you dont have a 25 BR die it might be pretty hard to make from 7mmBR.

Jim Kesser

I have formed 22br brass from RP 7br. I used a 6br die and gently sized the necks to 6mm then I ran them through the 22br dies. So with that being said I think it would be pretty easy to neck down from .284-.250. But with all that being said, if you have access to 6br brass I would neck up like Jim said.