I have no idea why stainless tubes were offered, or, why they went away. But, offered they were. I imagine pitting in the bores wasn’t a thing with stainless, but, don’t know for sure. Bet they are tough as hell.
Hard plating a surface gets you no more impact resistance than the base metal features. I don’t believe hard plating would help in a situation where the barrel steel was softer than steel shot an owner might put through it, for example.
Best,
Ted
It was explained to me, by Mike Orlen I believe, that chroming of bores is nothing like chrome plating a car bumper. It can never flake or peel away as can plated parts on automobiles. He explained that it is an entirely different process that actually causes the hard chrome to bond with the base metal almost like an alloy, that can never be separated. We were discussing cutting longer forcing cones in chrome lined barrels and I had expressed my concerns that lengthening forcing cones in such barrels would lead to failure of the chroming. He assured me that could not happen, and that he regularly does forcing cone and choke work on chrome lined barrels with no resulting issues.
How that process affects impact resistance I have no idea. My understanding over the years has been that the chrome lining of shotgun barrels is for abrasion and corrosion resistance.
