Honing out seating dies. Are they Hardened?

[CamoWhamo]

I'm casting and sizing bullets at .431 for my Miroku/Winchester 92 in .44-40. I have made some cerrosafe casts of the bore and it mikes at .431.

This opened up another issue as none of my .44-40 die sets could properly seat the .431 bullets.

I got around this problem by using a .433 flex hone to enlarge my Lee die just enough for the sized .431 bullets to be a sliding fit in the seating die. The Lee die also takes the expanded case necks without any problems.

It didn't take very long at all. Probably a total of 2 mins honing (cleaning and checking every 20-30 seconds).

While i was happy to try this with a Lee die, i thought i'd ask before i try to do the same with my RCBS Cowboy dies.
Are the RCBS dies hardened at all?

[EDG]

Your honing will probably be more precise if you use a barrel lap.

[Clark]

I have honed out two Lee 280 AI FL dies this week. Due to surface hardening, when I broke through with the carbide boring bar, instead of cutting from 0.298" to 0.308", I overshot on the first one and got to 0.316".

For a fixture, I used a Rem 700 take off barrel, and cut the chamber to fit a 7/8-14 threaded die. The lathe spider than then steer the die into being concentric AND parallel with the lathe spindle.

[DougGuy]

RCBS dies are harder than woodpecker lips. The hardening is quite a bit deeper into the metal than Lee dies.

[Mal Paso]

I lapped a RCBS 44 Cowboy Carbide Sizing Die with a piece of precision brass tube flaired with the expander and coated with fine diamond paste. The Carbide Dies have a solid ring of carbide but they sold hardened steel dies too.