I am fairly new to Mls and I've read alot of posts about JB bore paste.
Before getting into the blackpowder side of things, I only shot and hunted with centerfire and rimfire rifles and pistols, so this is where my experience lies.
One of the things I was taught as a lad in Alaska regarding guns ( by my Grandpop and my Dad) is that they almost considered it a sin to put an abrasive down a rifle barrel. They used bore brushes infrequently and depended on good solvents to eliminate fouling.
Maybe it's that age old Scots/Irish thing about trying to make a tool last a lifetime rather than purchase again. It seems to me that using any abrasive would be the same as a few hundred or a thousand rounds through that barrel, and in doing so, shortens the life of said barrel.
I don't know. I do know my Grandpop wouldn't part with a nickel if he could help it.
Not trying to be contentious, just don't completely understand the reasoning I guess.

I guess my question is,... are new muzzleloader barrels that much rougher than a center or rimfire barrel, that it has to be polished before it'll shoot right?