40-90bn to 45-100ish

[slimmpd]

Sitting on a decent supply of 40-90 brass but no gun to shoot it out of. I do have a 45-2.4/6 plus a 45-3.25 that I’m currently playing with. I know I won’t be able to reform to 3.25 but the 40-90 is 2.6 overall so should have enough brass to use on the shorter 45.
How do I make this work. I believe I need a form die or 2 but fire forming might work.
Thanks

[country gent]

fire form should work but also keep on mind when forming larger brass cases shorten. Going from 40-45 cal with the tapers you may end up with a case as much as .035 shorter. ( rough estimate) You have a set amount of brass in the case and sizing larger will cause it to shorten. They could be expanded up on a mandrel in a die to a very close fit also. A cerosafe casting of the cases internal taper would be a big help in making the mandrel also.