Every firearm acquired with your c&r license will have to be kept track of in your log book. You must use a bound book for your log book. Information on each firearm should include: description, model no, serial no., type, (ie bolt action rifle) caliber, date, and source of firearm. The log should also have room for disposition info, in the event that you transfer a c&r fire arm.
Transferring a c&r fire arm is allowed in order to enhance your collection, and not to make a livelihood from it. One way to help prevent entanglements with the ATF is to keep transfers of c&r firearms out of your collection to a minimum. I could be wrong but ATF seems to have some leeway in the interpretation of federal law in regards to defining someone who is engaging in the business vs. someone who is merely a collector.