WB
Dan, common 10mm or .40 S&W dies work fine.
Friday, January 17, 2020, 09:12

The Herter's .401 is simply a rimmed 10mm Magnum case 1.25" long. There is a little trick to making cases from .41 Remington that requires lite lathe work. That is the easiest I've found. The thick web portion at the base is held in the shell holder and cannot be swaged down in a normal press. So I simply lathe turn that little belt off. The cases also grow in length to something over 1.3" and need to be trimmed. I usually check them but mostly the rims fit the recessed cylinders, but they too could be adjusted if needed. Once you have usable brass they last a long time. You'll just have to check for Colt or Ruger part swapping. The too narrow Herters rear blade can be swapped for a Ruger part, I did mine. IF you could find a cylinder that could be fitted in theory it certainly could be rechambered. The dimensions are close to a Colt SAA cylinder in robustness, just different steel and treating. Another option I would kind of regret but is rational is to re-chamber the .401 Herters to the easier to live with .38-40 Win. There are only so many .401's out there. I have a cylinder so chambered for mine.

Is your barrel marked "Single-six" that has been X'ed over? Mine is.

Have fun and let me know if I can help. waterboyark at yahoo.