I’m sure this topic has been covered but I can’t seem to find anything on it. I am in the process of building a Walker Hepburn from a kit. 

I bought a barreled receiver that was smoked and had almost no parts with it. I’ve got a hammer, a regular Hepburn breach block and receiver, everything else is from the kit. I’ve got an aftermarket 32-40 Win barrel that will go on it.

I read up a little about annealing the receiver and people’s opinions, don’t think I’ll need to do that. I plan on nickel plating or rust bluing the parts. Do they need to be heat treated? The lower tang and lever and such I think not, but the breach block takes some abuse.

Logan

Johnny,

I bought the kit second hand, the receiver and hammer are original, everything else I will use from the kit. I’m more wondering whether it is necessary to case harden or heat treat the parts. Can I just go straight to nickel plating/rust bluing?

Logan

If the action and hammer are originals I can't see why they'd need to be heat treated? They already are heat treated for many decades now.

Logan,
You stated in your post. "I bought a barreled receiver that was smoked and had almost no parts with it."
Was the receiver in a fire?
If so, it should be checked for fire damage. If not, I'd agree with Marlinguy.
Rodney Storie told me that his castings used 8620 steel but that some castings in the past used 4140 steel. 
Untreated both steels should be safe with low pressure cartridges. However, the heat treatments are significantly different with these two steels and 4140 can become brittle if not properly heat treated.
I don't know an easy way to tell 4140 from 8620 and never could master the spark test. Maybe one of our members could help?
Otto