Much Chrome Plating is applied over a base plate of another metal. Back in the early 1960s, I was employed by a sporting goods maker in a Golf Club factory. I worked in the Iron Head department & became rather well acquainted with their plating process. I forget now just what the base metal was. may have been copper. Car Bumpers I am fairly certain use a similar process.
I will not argue the point as to whether or not plating is the proper term for shotgun bores, BUT I will say Emphatically it is NOT the same process used on car bumpers, nor on those Golf club heads. There is no undercoat to the gun bores & it does not peel or flake. Ruist does NOT build up under it, given the Wrong circumstances, it can rust through it, but does not rust under it. There is a difference.
