I don't use Bore Butter, because I did use it once according to directions, and got the ONLY CASE of after-rust in my bore that I have ever had with muzzleloaders, and I have been using black powder and BP substitutes since 1953.

Some unkind Bore Butter advocate had the effrontry to intimate that my bore was not clean when I lubed it up with that crap! He was wrong!

Two quarts of boiling water, followed by four or five several dry patches removes ALL POWDER fouling, leaving nothing but hot, dry bare steel (three quarts for cal. .58 & above), awaiting application of a rust preventative. (I don't know what is needed to get plastic streaking out, but suspect Bore Butter won't do this. You probably need a solvent like Shooters' Choice.)

I had used Birchwood-Casey SHEATH as a rust preventative from about 1963, prior to trying that damned BoreButter, and have gone back to using SHEATH! I've never had ANY rust in ANY GUN when using it! Modern rifle or ML!! This includes three years in Alaska, where EVERYTHING RUSTS!!