.338 Edge from 7mmRUM brass?

[Hicks]

For those of you who have one, is it possible to form .338-.300 brass from 7mmRUM brass? I've got about 200 pieces and I'd sure hate to waste them.

Hicks

[geargrinder]

You can, but your necks will be very thin. You're likely to split more than a few.

[davewilson]

yeah it can be done. i did exactly that making a couple dummy rounds for guys. i'd push it out in at least 2 steps, 3 would be better. then check your OAL, concentricity and wall thickness of your necks. the neck thickness doesn't change that much.

[Michael Eichele]

I have heard it said that if up sizing 2 calibers that the necks should be anealed after necking up.

I also agree that these should be sized in at least 2 stages. First 30 cal then 338.

[Hicks]

What kind of trouble would I get into if i just fire formed them?

[geargrinder]

You need to expand the necks. Fire forming won't do it.