I have seen the Robar finish that duplicates blueing used on a good friend's bolt guns. All his guns are custom guns, by the likes of Gowdy, McCulloch, Brownell, etc. All are pretty old, and old school except the finish. The guns have been around the world, used hard, and look pretty good to this day. The edges wear in a similar fashion to a blued gun, but, rust resistance is much better.
Sorry, but you are likely to be the first we know to try it on a double. I 'gotta believe a model 23 would be a good candidate (no, I'm not trying to stick a thumb in Don's eye, but it is a modern gun and one could expect a lifetime of heavy use with one)
for an attempt at it. Robar would be able to do it, and likely warn you of any pitfalls.
Good luck. Sounds interesting, anyway.
Best,
Ted
