There is no such thing as a "best firearms finish"! This one is better for looks, that one is better for wear and the other one is better for corrosion resistance. A lot of firearms finishes are the same as the "other one" but re-packaged under their own label. One of the well known ones is not even a firearms finish. It's made for dumptrucks and bulldozers but their advertising would have you think that it's the best thing for guns since smoke-less powder.
Another factor is how well the particular finish will burnish. If it won't burnish at all, it can't be used on internals.
Tests are designed to simulate real world conditions but at an accelerated pace. Who's going to subject their firearm to 5% salt water at 800 degrees mixed with pure oxygen and sprayed on for X number of hours? But the idea is that that particular test will show how well it will withstand the sea air on your boat.
If you're looking for corrosion resistance, look at Gunkote 2400 Series over Zinc Parkerizing. Magnesium parkerizing works well too but the Zinc based stuff is a little more coarse and provides better adhesion. I recently saw that Cerrakote did better at a few tests but I'll stick with Gunkote over Parkerizing for now.
If you want to do a simple test at home to see how well "their finish" does against "that finish", coat a metal part (NOT Aluminum) and drop it in a can of Acetone or gasoline or concentrated Chlorine overnite. The next day, pull the parts out and see what they look like. If you tried that with duracoat, the finish will be 100% gone. If you used Gunkote, the finish will be 100% unaffected. Not a realistic test, you say? Some firearms cleaners and lubes contain Acetone. Gasoline does sometimes splash and you can smell the Chlorine in some pools from a half mile away. Keep yer powder dry, Mac.
Tuff-Gun Finishes. The Name Says It All.
Mac's Shootin' Irons
http://www.shootiniron.com
