I don't know of any coating that would help you there. Hard Chrome plating is all I can think of that would fix it. It sounds like the rounds feed in at to steep of an angle. Have you tried trimming the lips on the mag back a small amount? That would allow the front of the bullet to ride up more, allowing a shallower angle when it hits the ramp. Besides Hard Chrome, a feed ramp insert would work too.
Our Tuff-Gun finish uses heat throughout the process...application and curing. However, the heat is never high enough to affect the temper or metallurgy of the metal. This is another area where a microprocessor controlled industrial curing oven beats the kitchen oven. When I say *** degrees, it stays within a degree of where I set it for exactly how long I want it to stay there. Keep yer powder dry, Mac.
Tuff-Gun Finishes. The Name Says It All.
Mac's Shootin' Irons