Guys,
I believe the brass sheet I use is alloy 260 which I buy in 2' x2' sheets, 1/16 for thimbles & nosecaps, and 1/8 for buttplates, sideplates, and lockplates. For the pans I use free machining yellow brass bar alloy 360, no noticeable color difference. For barrels I use CDA alloy 936 bronze which is noticeably more red than brass. All from McMaster-Carr. I have not encountered any wear problem with brass as opposed to wrought iron, but modern steel may be better wearing than the original materials. With a brass lockplate or a bronze barrel the metal will turn a rich and dark brown at the first shot, so to keep the brass bright & shining is a futile task.
Jim