I have worked in a few machine shops that use black oxide as a finish on some of their parts. Its a really simple process, why dont they use black oxide on firearms, seems like it should work.
My wife use to work in a machine shop and they had an area where they did black oxide. I use to prep my gun parts and she took them to work. The finish product looked pretty good. To bad she doesn't work there any more. ...
I used to have a Ruger Mark One that needed refinished. My step-dad worked at a place that put black-oxide on tools and such. He got laid off so that plan went down the drain after he got a new job...