I absolutely LOVE the look of color case hardened lever guns and classic rifles. I have been toying around with the idea of doing a custom action, either a Defiance or Ultimatum, and case hardening it as opposed to cerakote or DLC or some other finish. My question being, I know that color case hardening changes the chemical makeup of the metal however I am curious if doing so will mess with the tolerances of the action itself?
Would color case hardening a custom action have a negative impact on accuracy or are is it not a big enough deal to matter?
Would love some educated opinions on this idea.
First, you have to decide exactly what you want.
Color Case and Case Color are not the same things.
Color Case: Basically, take a piece of steel and throw it into a pit with smoldering charcoal laced with bone, leather, hair, and wood to bump up the carbon content. The heat allows it to leach into the steel, making it harder on the surface once quenched. the organic impurities laced in the mix is what gives the psychedelic color appearance.
Hammers are made this way.
Case Color: It's a process designed to emulate the color without being so invasive as the temps are lower. Color Case works best on big, dumb shapes. Thin-walled high boy receivers, U shaped parts, things like that are a bit more challenging as they have a tendency to distort. This process is intended to deal with that challenge. The stuff I'm familiar with uses various cyanide type salts. -Not something to be cavalier with... It's also not really "hard" per say.
We did a fair amount of both when I worked at Dakota Arms years ago.
General rules with Ferrous metals:
416R type stainless, the most popular material used today by the bulk of aftermarket "SS" actions, may take on some of the coloring qualities, but it's not going to be correct. I can't speak to what it will do metallurgically. 416 has some behaviors that really need to be explored before doing something like this. The last thing you want is a grenade... Typically, steels like 12L17, 4130, 4140, 8620, and I'm sure a litany of others, respond best. Those are all generally classed as "carbon steels"
Another nice looking finish is Ferritic gas nitride. Parts do have to be blasted slightly first to open up the surface and put a "tooth" on it. Usually, a light glass bead is all that's required. Its an atmospheric process vs soaking in a nitrogen/ammonia type salt. Satin gray vs the blacks that salt bath creates.
Just know that the folks doing this kind of stuff are relatively small. They'll need an FFL when doing serialized gun parts over a state line.
Hope this helps.
C.
