I think I am convinced that a lot of people applying "bore butter" are doing it incorrectly. I use BB I have used for 6/7 years now but the way I apply it seems to be different than most. I have know idea whether BB "seasons" a bore or not - I do know that it reduces fouling especially plastic fouling dramatically and realy makes slean up significantly quicker and easier.
This a a post that I wrote early in the week but it is applicable here:
Addressing your question about BB, and I can't believe that RB & I agree on something, his post to you IMO is right on line with my feelings.
I really do not know if "seasoning" occurs, but was does occur is less fouling mainly from plastic for me. I shoot my guns a lot and in Idaho sabots are legal so I go through a lot of them in the year. It significantly reduces plastic fouling and powder residue. I use BB in combination with another natural product Wonderlube to maintain my barrels and guns.
Another thing unrelated to ML's, I would relate to you. The one thing that made me more of a believer. I am now using BB on my screw-in shot gun chokes and on my ported trap barrels. The build-up of plastic that I use to recieve on my chokes was terrible and really not fun to clean. Every once in awhile I would shoot a round and it would be followed by a big blob of plastic residue releasing from the choke - well not any more. Bore Butter if applied right will reduce fouling..
When I apply BB the barrel is hot, from the hot water flush. If I am treating a "traditional" gun I dry swab the barrel a couple of times and then use a can of air to blow through the breech plug to push any residuel water down the barrel. Then dry swab again, of course with an in-line no air needed with the removal of the breech plug. It is my feeling to make sure the barrel is dry and hot before applying BB. Instead of using patches to apply the butter I put it on a bore swab, and as RB says rather heavily, then run the swab down the barrel, here is the amazing part, the barrel literally sucks the butter from the swab. When you pull it back out it will be near dry and fluffy again. I will do this same routing 2-3 times making sure to get all the barrel. A dry patch worked up and down and down a couple times and let here cool. The lasthing you want in the barrel is a glob of this stuff sitting there exposed.
Now when I go to the "range" (a rock pit) I will shoot 30/40 rounds typically. I do wet patch between shots. I take a zip lock bag of water damp patches as my spit patch. When I get home I use 3/4 patches wet with windex, that is all it takes for me to come up with a really clean barrel. I usually do not use a bronze brush because i do not have any lead fouling and the plastic isn't sticking. I will reapt this BB routine maybe 6-7 times a year with a particular gun depending on how much it has been shot or how hot the barrel got from shooting. Most often it is just patch clean and Wonder Lube til the next time it comes out to go shooting.