I use brass for both chambers and barrels - in the form of a Payne Gallwey pattern brush - and I'm very pleased with them.
I would imagine that any plating would wear off the contact areas quite quickly, so don't really see the point?
I have heard some people say brass is a problem (corrosion?, electrolytic action?) but I can't see any problem myself. These people recommend phosphor bronze.
Brass is supplied with many 'high end' guns as part of the standard kit, so I can't see that there can be much of a problem.
