Heating any shotgun receiver without controlling the temperature and heat duration is potentially dangerous and can damage guns and potentially harm shooters. If a shotgun receiver is heated to critical temperature, such as that required for the bone charcoal hardening process to be effective, then the structure of the metal has been changed and the metal should be tempered back to provide some elasticity. Otherwise, the receiver is as brittle as glass and may crack or shatter upon firing of the gun.
Incorrect tempering of receiver metel is the inherent flaw in the use of the high heat bone charcoal process when applied to shotgun receivers. A dangerous situation may develop as a result of incorrect tempering of the receiver metal after the high heat bone charcoal coloring process is completed. This is particularly true of older shotgun receivers, made prior to ww2. Factory tempering specifications were inconsistent, as receiver metallury formulas changed from time to time. Unfortunately, much of the original factory hardening and tempering specifications have been lost. Even the best of mechanics are only guessing when they attempt to correctly re temper a shotgun receiver after subjecting it to a high heat bone charcoal hardening process.
A low, controlled heat process, combined with specific chemicals is the safest way to recolor a shotgun receiver. So long as the heat is kept low and controlled, the original receiver metallurgy and heat treatment is not changed. No harm is done to the gun nor is there any potential for danger to the shooter, as a result of the re coloring process.
