After shooting I use a bore snake with a little Beretta gun oil sprayed on the first few inches of the bore snake - I repeat this about 3 times on each barrel. I follow that by a mop and oiled patches - until the patches are pushed through showing they are clean or with minimal residue. Occasionally I will use a bronze brush as well.

I use the same Beretta gun oil as a protectorate for the outside of the barrels and the other metal parts.