I can't think of the exact name at the moment...but I use a product from T/C. I think it's called Bore Butter 1000 or something very close. Whatever its called, it isn't oil based so it will not turn into a tar like substance when super-heated by the shot. It makes cleaning very easy.

I wouldn't recommend using an oil based product because like stated above, when it is super-heated, the oil turns into a tar like substance that ishard to get out of the barrel.