I would assume it is nowhere near as “corrosion proof” as hard chrome?
Again, there really is no such thing as "hard chrome' unless you're doing a hydraulic cylinder. The QPQ process, Quench Polish Quench, is another derivative of Salt Bath Nitriding, but uses a different set of chemicals. It isn't much for repelling water, but it is hard, as it is also a thicker coating, and essentially case hardening, as are the others.
As mentioned before, the barrel profile on your "rifle" would be too thin for such a treatment by anyone competent, as the heat levels are very high, and you would risk annealing.
Can't figure out why a "hard charger" such as yourself, who is so "tough" on equipment, wants to try keep rifles looking new? Boots, knives, jackets, and everything else that actually gets used more than 300 yards away from the truck, gets worn out, scratched, and marked up. Why not a rifle?
Routine maintenance solves all of the problems, and Pincher Creek is a long ways from the ocean...
R.