doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Ideas on re-sizing Rocky Mountain brass 10 g hulls

As thick walled as those cases are I can’t see any practical way to resize them. Totally unlike drawn cases, which are very thin walled. You’ll be better off either getting new cases (look at the cases at Track of the Wolf) or turning them down—a very delicate lathe operation.

YES, like Joe said and send the old cases to ME !!

Mike

Maybe you’re looking at the wrong end of the hoss.

Are your chambers in good shape? I see a lot of old guns with chambers which are tough as heck. If yours are rough polish them is a good first step.

The chambers are fine, it is a relatively new Spanish double, I have other new and used RMC hulls that fall out of the gun with no problems.. The problem appears to be that whomever I bought the hulls from used them in a shotgun with chambers that were not as tight as the chambers on my shotgun.

What is the interior dimension of your 10-gauge chamber just above the rim? What is the diameter just above the rim of the existing fired cases that will fit? What is the diameter just above the rim of the fired cases that won't chamber? That would determine how many thousandths you would need to resize.

SAAMI spec is here, page 19: https://saami.org/wp-content/upload...shell-2015-R2019-Approved-2019-04-23.pdf

Diameter of 10-gauge 3.5" just above the rim is 0.854 - 0.009, meaning that your 0.846 is right about at the very smallest diameter possible. Not knowing the dimensions you're working with, If I were you I would try opening up the 0.846" hole to about 0.850" or 0.852" for the first inch or so and see if that takes care of the problem.

Are these cases turned from brass bar instead of drawn? if so my previous advice is wrong, bsteele's and/or John E's is correct. Turned cases act differently than drawn.
Mike

They aren't drawn like the Magtech brass hulls, they are CNC'd from bar stock.

Build an online friendship.

Box them up and send them to someone here that can machine them for you.

Or sell them
Or reem the chamber

Having a set of progressive dies made, so that you can draw them to a slightly smaller diameter might be a fun project, but it’s not homeowner type stuff.

CZ, would you really consider altering a gun to fit someone elses used brass?

If the brass only goes half way in the chamber, then it is likely the thinner wall that's hanging up. At the least, maybe put some calipers on the brass that work correctly, and the bulged brass, maybe do the sharpie low budget dykem, if the markings don't show without it. The expanded brass is probably not at the head, if similar brass can fully chamber, likely the thin wall would have expanded.