Colt D.A. 41

[otelo]

Looking for a nickel, fire blued hammer for a Colt D.A. 41 Thunderer. Any ideas.

 

[dfariswheel]

There's no such thing as "A nickel fire blued" gun part.

Either the part has a nickel plated finish, or it's been blued by one of the heat methods that gives the part a brilliant blue color.
It can't be both.

Due to the rarity of usable parts for these older models, you're option are probably going to be to buy a usable part (if it can be found) then have it be either bright nickle plated, or send it to someone like Doug Turnbull and have it fire blued.

You can ask about a usable hammer here:

http://www.coltparts.com/pt_1877da.html

 

[otelo]

It is nickel on the sides with fire blue down the back side and front, like the trigger. All screws are fire blued. This is something Colt did.