Here is an Old Bore Butter thread here back in 07, These threads are ALL over the entire WWW, There is more NEGATIVE on Bore Butter than all of us Combined have the time to Read
https://www.modernmuzzleloader.com/threads/bore-butter.5636/
Bore Butter is the FARTHEST thing from what I would use to Protect my Guns. That being said, There is NO doubt it would work,
as long as you knew for ABSOLUTE sure you have the bore METICULOUSLY Clean, and you knew for ABSOLUTE sure the Bore WAS BONE DRY BEFORE you Added it, While these things sound SUPER EASY and Straight forward (and they ARE for us Seasoned Guy’s) But FACT is This can be TOUGH with Sidelock Muzzleloaders Since you can
NOT easily look in and Inspect them, Especially New Guy’s just getting in the Hobby/Sport. If by chance you didn’t get the Bore
THOROUGHLY Clean, and there is even the
SLIGHTEST hint of Moisture left behind, Think about what you are doing when you Slather your Rifles Bore with TC Bore Butter? You just
“SEALED” Your Bores Fate!! Rust, and Pitting are
ABSOLUTE SURE to Follow! As you go on with Everyday life, Your Muzzleloader is Propped up in Your Closet Etc.
ROTTING AWAY
Not to mention dealing with getting that Junk out of the Bore before Shooting, Bore Butter is HARD as a Brick in Cold weather, and RUNNY as Water in Warm weather. The best place I found for it was the Garbage
It Simply Can
NOT Compete with a Quality Gun Oil to Protect/Preserve your Muzzleloading Rifles