Scotchbrite can be used to card barrels, but it is more abrasive than 0000 steel wool. Rub too hard with it and you will be right back to bare steel. It will actually scratch glass. I learned this the hard way when it first came out and I used it to scrub some dried petrified bug guts off of my truck windshield. Fortunately, I only did a couple small spots outside the normal viewing area.
https://docs.google.com/document/preview?id=1ZIo0y746UsSRZIgRuuxwAbZjSBHitO_EanvwLYc-kGA&pli=1Above is a link to one of Dr. Gaddy's Damascus refinishing technique articles. I don't think he ever wrote a book. The Angiers book noted above is a good reference, and there is a ton of information on the internet and in various gunsmithing books. Always best to practice on some junk barrels to learn the process. Logwood is a dye extract from wood chips from the heartwood of a tropical American tree. I never used it on barrels so can't recommend it one way or another. I've used Neidner's formula a few times and found that it gave a blue-blue, not a black-blue, no matter how many rustings I did. It's a nice finish, but it may not be what you're after.
