A few years back, GUNS & AMMO ran a seven or eight part series on building your own 1911 starting from just a frame. The last article dealt with finishing it.
I made a note of certain info that appeared in it.
Finishes are tested for rust resistance by putting them in a cabinet at a fixed temperature and humidity, and timing how long it takes for rust to appear. There's a continuous salt spray on it, also, as I recall. All intended to accelerate rusting.
Ordinary, polished, chrome moly gun steel, when placed in such a cabinet, shows rust after half an hour.
When blued, it shows rust after one hour.
When parkerized, it shows rust after two hours.
A stainless steel alloy suitable for gun use shows rust after 60 hours.
Electroless nickel and hard chrome were up in that range, one went 50 hours and one went 70 hours, just off the top of my head I don't remember which was which.
Robar's NP3, which is a nickel-teflon hybrid, went 300 hours.
Some of the other high tech finishes went as long, or longer. In some cases, the tests were terminated at 2000 hours with no rust present!
For a really tough situation, like keeping a gun on a boat in FL, or some such, I'd say start with a stainless gun and then get NP3 or another hight tech finish put on top of it.
