It should also be noted that parts can be recolored without rehardening. The temperature range wherin oxide colors form is well below the kind of temperatures likely to warp metal. Dr. OG recommended doing this. Note that most of the colors in CC are within the range of iron oxide colors, but some depend on other stuff such as is found in the bone charcoal. Masters of the process can control to a significant extent the pattern (sttripes/spots/mottled) and the predonimance of color (mostly blue/mostly brown/a dash of green/almost grey/etc). Usually, one wishes for the master to recreate what was originally on the gun.