Resize 450/400 3 1/4 to 450 3 1/4?

[analog_peninsula]

Is there any functional reason why I shouldn’t try to run the 450/400 brass through the 450 expander? Inquiring minds want to know.

 

[Mark A Ouellette]

Is there any functional reason why I shouldn’t try to run the 450/400 brass through the 450 expander? Inquiring minds want to know.

That's a pretty big expansion that might split the cartridge case neck. Better aneal that very well.

A better path may be to first aneal the case necks then fire form using a small charge fast burning powder and some type of lightweight filler in lieu of a projectile.