Bore butter is basically just a wax coating. If you have a perfectly clean bore, a coat of wax evenly applied would be a protector from the elements but nothing more. If the bore is not perfectly clean and you coat it with wax, you have trapped any impurities/residue/moisture beneath that layer of wax and have provided a nice hiding place for corrosion to occur.

Clean and shiny with a light coating of good preservative... works for me.

Bore butter works ok as a conical lube.