Using Barricade in your bore as a rust preventive is okay so long as you wipe it out before shooting. Since you do not slather on the Barricade, all that is necessary is to run a few patches through your bore to wipe it clean before shooting. If you wish to make sure, for your piece of mind, that all Barricade is removed from your bore, you can use a bit of lighter fluid or similar solvent on a final patch to remove all of the Barricade. But, in reality, a few dry patches will do a plenty good job of removing the Barricade from your bore. The problem with petroleum products in the bore is when they are used as patch or bullet lube. I use and recommend Barricade as a rust preventive in and on all metal surfaces with the provision that if it is used in the bore, that the bore be wiped clean before shooting. Properly used, Barricade is an excellent product for use on muzzleloading guns.