I think if I were going to try it I would do a sample piece of scrap metal to verify the results. I think I will try it myself just to see if and how well it works.




JMH

I tried medium Pace on a lowwall that had been polished by a previous owner. I blocked it with 320 to give the solution something to bite on. I left it on 20 minutes with some change, then tried the flip side for 30 minutes, washed it off then did the curved surfaces. Some color, but certainly not as much your Sharps. Its more silvery rather than darker and blue. I’m wondering if the difference of old metal to the new, modern alloy, or if it might be the difference between heat treating methods is the issue. Many variables for 2 chunks of metal. I’ll get more picante and try again and/or try the ketchup method.

Yes, it is the acid content.  Vinegar is acetic acid (diluted in water of course)

The Sharps pictured was French Gray when he started, its also a C Sharps receiver if I remember right so the steel is modern and was hardened. Maybe already being done in the French Gray let it darken up like that. No Clue! I've got a C Sharps action that is still in the white that I was going to try this on and see what happens myself. If it doesn't look like I want then I'll clean it off.