Re: Form brass for 7mm Rem. Mag. from 338 Win Mag
Welcome to Long Range Hunting!!
I've never done this 'thicker case neck' procedure on purpose but I'd imagine I've done it without knowing!
Sounds like a backward 'tight neck' scheme, should work I guess. Make sure there's enough room for the neck to let go of the bullet and you're set, I'd guess.
Let us know how it goes.