3 replies to this topic

[pat k]

e.

[full auto 45]

Let me try.
1- All guns, yes all guns, left the factory blued. Through the years the bluing process changed some. That is why some were darked and duller then others.

2- When a gun went back to be reworked at a arsenal, there were several, they would parkerize them to protect the gun from rust better. Again I believe that over the years, the process would change and that is why the color difference. Plus you have several locations an their "mixture" could be different.

3- The newer parkerized guns are a lighter Grey and will change as they age and get used and oily.

I could be wrong, but I'm sure someone will let us know. Now if you want all the metallurgy terms and processes, PK or someone like that can give all the details.

[Hawkeye_Joe]

I have read that the way that the greenish grey park was made was accidental. When the park was put on the guns had cosmoline applied too quickly and the interaction of the two caused the greenish hue.

[LSU Tiger]

Some of it is the chemistry of the process. For example, M-1 rifles left WRA and Springfield with the same parkerized finish. However, WRA used a different chemistry than did Springfield. Different colors. But, to the inspectors, it met spec. Also, the heat treating effects the final color. Slides of M-1911A1s made by Colt sometimes have a two-toned slide. The actual chemicals used 60 odd years ago have been banned, something about one-eyed offspring... The "new" chemistry does the same thing to metal, but can be altered for color. The "Dulite" finished Thompsons were sand blasted to clean the surface and to elimate polishing off milling marks. The added benefit was to produce a semi-matte finish when dipped in the Dulite. Dulite, by the way, is a proprietary firearms finish that is still in use. It requires heating the solution to something like 350F and dipping the part for a period of time.