I'll second the use of Break-Free CLP. I first started using it in the Corps as it is the milspec cleaner/lubricant/protectant authorized for use on the M16A2. It's some very good stuff. If you apply it correctly (i.e. sparingly), it drys to a non-dust collecting protective finish. It contains solvents than do a decent job cleaning powder fouling and while wet provides a standard oil like lubrication, once dry it leaves a film of Teflon on the metal parts for lube and a protectant that prevents rust. It's the best lube out there and I use it on all my guns religiously.

Mike