Your "bound book" can be simply a three ring binder with a few sheets of paper in it that records acquisitions and disposals. You can make your own or just surf the web at sites like
Welcome to Cruffler.com! for leads. All I did was find a few .pdf files online, printed them out, punched holes in them, and put them in a binder. That specifically does meet the criteria for the
BATF, according to their own agency.