Don't use bore butter in your centerfire and don't use mineral spirits as the one post suggests. Get youself a good quality solvent which is made for cleaning the bore by breaking down and disolving the copper and lead deposits and powder residue. And use a bore lubricant if you plan on storing your firearms for an extended period. There are many good solvents out there like Hoppe's Benchrest, Breakfree Bore cleaner, Outers Bore cleaner, etc.