So far I have been using Oregon Trail 200 grain .427 bullets designed for the 44/40. I run them through a RCBS lubamatic with a .423" sizer die and they seem to work, except that they are very short and I'd like a longer heavier bullet. I checked with Missouri bullets and they have a .430 300 grain bullet that I would like to try but am concerned about pushing a .430 bullet of BIN 18 through the .423 die. Has anyone had a similar experience and can provide guidance?

Have you slugged your bore? I use a .425 die in my Lyman 450 lubesizer to size cast bullets for my 404. I use .429 44cal copper gas checks and they size down easily in the die. I cast my own 400gr multi groove bullets.

Problem with sizing down too much is you can lose a good depth of the lube grooves on the bullet so it is maybe not so much an issue with the swaging process in the die but what you would have left to hold enough lube for the passage down the barrel. Mindful that we are talking of passage in a long rifle barrel and not a short pistol barrel where only a small amount of lube would suffice.

Accurate Moulds offer several size moulds for the 404.

Am getting my barreld action together so I will later order a mould for it.

Plan on using 44 gas checks, and a few years ago I spl ordered a RCBS .425 lube sizer die.

JW