I use Montana Xtreme gun oil, break free CLP, Birchwood Casey Barricade, or Rem Oil with Teflon to protect the bore. On some rifles I use Montana Xtreme Bore Conditioner. Which ever one is near me when I am ready to put my rifles away. All of them work fine.

Before I shoot, I clean the barrel with isopropyl alcohol on a patch, then a couple of dry patches. As for the breech... push a clean patch down there and shoot off a primer or cap and blow that oil into the patch. If you see burn marks on that patch, your ready to load and shoot. Never had a problem with the petroleum VS powder issue that way.