Forming the 7MM Super Mashburn

[dan belisle]

I was wondering if you could help me ? I have a model 70 build 77 mm mashburn it was a gun that was given to me unfinished ,an old friend passed and here I am , I’ve tried to make casings for the rifle have the die set but still can make them chamber . Wonder if a Fire Forming might help and where can I purchase such a thing .
John F
johnfillier@hotmail.ca

You fireform them in the chamber of the rifle. Neck your brass down to 7mm and push the shoulder back (going by memory here, long time since I played with one). Depending on your chamber and brass interaction, you may need to make a false shoulder for the fireforming. Annealing the brass helps, otherwise expect cracked shoulders from pre fired brass. Trim to length. Use whatever 7mm bullet you like, and 7 Rem Mag loads, and fire away. Presto, 7 mm Mashburn brass. - dan