Nickled luger?

[BILL]

The older Colt charcoal fire-blue (using bone, charcoal, leather, and other organic combustibles) doesn't acutally pull carbon out of the steel but creates a high carbon atmosphere. The gun parts were heated to a cherry red glow and often the bone and charcoal were packed around them and wrapped in rawhide. This was then put in an airtight container to create what is known as a reduction atmosphere. The hot steel, upon igniting the materials, absorbed the carbon that was given off (since it is starved for oxygen it takes in the carbon rich atmosphere). This produced brilliant purples and reds and blues on the frames. The whole process was a guarded secret but now is fairly well known. No two specimens turned out the same, which adds to the beauty of the process. Rust bluing, on the other hand, is a chemical process applied to the surface of the steel which has an acid base and creates a black oxide finish on the 'rusted' surfaces. Rust bluing is extremely labor intensive.