I personally am not a bore butter fan. I use it to lube conicals and now that I make my own lube not even for that...

The way they told me to use the bore butter is after I scrub the barrel back to bare metal almost... I then pour boiling water down the barrel to get it really hot, and I mean hot! Then I run a wet alcohol patch down it to drive the moisture out of the barrel. Then a dry patch or two down the barrel to make sure there is no moisture. then I take some bore butter and start packing it around the outside muzzle of the barrel so it begins to melt. Then I smear it down the bore with patches. After I am sure I have the entire inside of the barrel covered. After the barrel is cooled, I take dry patches and try to patch out the excess bore butter.

As the barrel is cooled the metal will suck the bore butter into the pores and this is supposed to season and protect the barrel from rust.