Pohill, did you mean you loaded unlubed bullets into charged cases? If so, I don't think simply applying some Bore Butter to the exposed surface of the bullet will be enough. If you intend to pull any unlubed bullets and then apply Bore Butter prior to reinserting into the cases, I don't believe you will be happy with the results. Bore Butter becomes soft at room temperature. However, you might get acceptable results by thickening it up with the addition of either some bees wax or paraffin wax.
Good luck, and let us know how it worked out for you.