gzig: Don't use once fired cases to form your Mashburn brass.Start with new brass.

On the left is a new 300 WM case that has been passed through a Form/Trim die before being fire formed. A Pass through a FL Mashburn die should result in the same thing and no case wrinkles/buckling.

The next two cases are live fired 7mm Mashburn Super,fully formed. There is not much progression, other than a bit less taper for the Mashburn case.


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Last edited by BobinNH; 02/28/16.


The 280 Remington is overbore.

The 7 Rem Mag is over bore.