Dave-
Firelapping consists of shooting lapping grit coated bullets down your barrel at modest velocity. You can buy kits that let you impregnate bullet surfaces with grit, and then hand load them, or you can buy pre-coated bullets. The Tubb Final Finish Bore Conditioning System, named after rifle competitor David Tubb, is probably the best know kit of the latter type. Cabela's, Brownells, Midway, and Midsouth all carry Tubb's bullets. Directions come with the bullets, so I won't bore you with the details here. I don't believe that there is any name brand, commercial source for pre-loaded 444 firelapping rounds, it's a handloader's trick.