>(There's also the case
>hardening on the receiver, no idea how to do that.)

That, specifically? Isn't difficult. Grab an oxy-acetylene torch, heat it, dunk it in water. Done. (yes, there is a bit more to it, but not all that much). That's what you tend to see on old guns, really, that 'flamey' pattern? Is just that. Heat up, dunk in water. Or, if you're short on carbon, heat, dunk in oil, leave for a bit(the longer, the more carbon you get), then heat again and dunk in water.

...!
Stoke Mandeville, Esq & The Victorian Ballsmiths
"Nobody Want Verdigris-Covered Balls!"