Rcbs cowboy dies work or not??

[mikld]

Expander plug has a standard and a larger one. The seating die also has a wider mouth to take larger diameter bullets. The .454 bullet was scraping lead and brass in the Lee dies I was using. I loaded 15 when I got these and no scraping or shaving lead. I can only speak for 45 right now. Waiting on mold I ordered for the 45-70.

This is what I was thinking too; larger ID seating die...

 

[Real Gun]

Seating should not affect the diameter of the bullet, only the nose, if using a suboptimal seater stem shape. Any other lead perceived as "shaving" would actually be too heavy a crimp while the bullet is still being seated. The shaving I know occurs with not enough flare or without a chamfer on the case mouth. The question though, with die diameter a factor, is at what diameter the die forms and holds the case mouth while crimping the roll desired. That could be larger in a cowboy die, in proportion to the sizer and expander. The end result is a cartridge without the bullet shape printing through the case and without any lead mushrooming around the crimp groove, i.e. it can pass a cartridge gauge, given a trim length that works consistently.