i found this statement from Alex Zimmerman, founder, CEO of Guncrafter Industries
“We use Melonite finish on most of our pistols. It is a black nitride finish done in a salt bath at about 950 degrees.
In our opinion it is the best finish on the market for hard use pistols, it is EXTREMELY corrosion and abrasion resistant and has a rich, deep black color.
It also has a very low coefficient of friction, making for a smoother cycling pistol.
Please understand that where ever metal is rubbing against metal (under slide stops and thumb safeties, on the slide and frame rails etc. ) there will be wear marks.
However, the beauty of Melonite is that it provides protection even if the black color is worn off, the Melonite process penetrates several thousandths deep with a file hard, rust resistant surface.
Before being Melonited we blast the parts with aluminum oxide to texture/pickle the surface, this allows oil to seep into the open "pores" of the material as the still very hot parts are dipped in a penetrating oil right after being Melonited.
Because this oil is trapped in the pores of the metal you should never use a chemical solvent or degreaser, products with Trichloroethylene, Ammoniated Solvents, or strong Alkaline Solvents, Gun Scrubber or brake/carburetor cleaners on your Melonited pistol. The degreasing qualities of these products will remove the oil trapped in the porous surface and as a result the Melonite finish can end up looking blotchy, dull and uneven.
Instead, use WD40 or a similar light oil/lubricant as a cleaning agent followed by a LIGHT coating of a heavier oil/lubricant to the exterior surfaces of the pistol to bring out the natural rich black color of the Melonite finish.”
I have seen Guncrafter state tha MPro7 was safe for use on melonite. I have used it on Nighthawk’s black nitride and had no discoloring.