It’s a well-known and dismal fact that any steel suitable for use in firearms will rust. Since rust is bad, all sorts of solutions to the problem have been tried over the last 400 years. Bluing (which is a form of controlled rusting) is the most popular, but many’s the blued gun that has rusted all to hell.
Plating has been tried. Charlie Askins used to swear by Marker Machine Company’s Black Chrome plating. An acquaintance of mine sent them a Ruger Model 77 .338 and they screwed it up completely.
Parkerizing, a form of metallic coating, was developed just before World War I, and the U.S. military made heavy use of it. It was effective because it was non-reflective, fairly rust-resistant (if you kept it oiled) and wore fairly well. It was, however, exceedingly ugly and has not been used on civilian rifles.
Now, we may be at the dawn of the rustproof rifle. A number of top-drawer custom gunmakers are offering steel finishes that are damn near impervious to everything. These finishes vary in their composition, but all are third- or fourth-generation. Earlier versions were either too thick or too soft, or too prone to cracking.
John Lazzeroni was the first in the pool with a coating called NP-3, which is a mixture of electroless nickel and Teflon. All Lazzguns have been so coated from the beginning, and it is terrific stuff. It even looks nice—sort of a dull pewter color.
Mark Bansner uses K-Kote as his standard finish, Charlie Sisk uses Cera-Kote, and Ed Brown offers Gen. III. All are very thin, very hard, zero maintenance, and durned near indestructible. But they are not cheap. It costs about $250 to $350 to apply them.
Having had more than one rifle rust despite taking all precautions with it, I am a big fan. I dislike most of what passes for progress, but not this.