Butch's Bore Shine is an exceptional product. I've been using it for several years. They also have a "Black Powder" version that I have not messed with.

I use BBS to:
[ul][*]On new bores to quickly remove all packing lubes and varnish buildup.[*]Restore neglected rifle bores that I work on (about6a year). Helps to remove rust, excessive fouling and "seasoning" buildup for difficult to load rifles.[*]After shooing conicals to remove lead.[*]After 100 sabot rounds within a bore to remove any plastic buildup.[*]Once or twice a year to clean down to the bare metal.[/ul]
I use about a quart of BBS every year. Superb Product!