sproulman
Just as point to mention, you probably already know that I continue to use BB in my barrel care routine. But I think I mentioned the last process after the barrel has cooled to room temp is to run a couple of clean patches down the barrel to get the last of the excess BB then use a high quality oil such as sheath or Break Free Clp to oil the whole thing inside and out. That might help those areas that may be missed. Remember I am not using real BP. If I were using real BP I would stay away from the oils as recommended by TC and others.
Heat plus petroleum oil equals tar! That's what causes the heavy fouling when shooting a muzzleloader with conventional petroleum based lubes. The problem of heavy fouling was one not encountered in the old days, as the oils used then were all natural' whale oil, bear fat, deer tallow, etc. Petroleum based oils were not discovered until the mid 1800's, and during the Civil War, fouling did become a problem. If you do use oils remove all traces of oil from your muzzleloader by cleaning the bore with hot water and a detergent before shooting Black Powder.
But also remember the quote is by the company selling BB. I do not use real BP so I can not accurately so whether this is a fact or not.
anda few sentences before this information it recommends NOT using BB with a sabot barrel at least not lubricating the sabot with BB. To maintain a dry bore for sabots.
So it really comes down to what works for you and your gun..