I have one set of barrels with chrome bores. They were made in Italy some 50 years ago. I have had no problem with them over those 50 years. Stan is indeed right, the chroming of shotgun bores is an entirely different process than Chroming Plating a Car Bumper. I am not positive what the correct terminology is, but I think it Actually, Not Plated per se.
ANY steel can rust, even the most resistant of the Stainless ones. When stainless does oxidize (Rust) it will normally Pit worse than a non-stainless one. This has been observed by boaters who carried both stainless & blued steel revolvers under identical conditions.
As Stan said though Rust will not form beneath the chrome in a shotgun bore as it does on a plated part such as a bumper. IF it does indeed rust it will do so Through the Chrome, not under it.
