Scott nailed it. It is the record of arms you acquired and disposed of under your license- ONLY.
M1 carbine purchased from a dealer 3 states away, and I sent him a copy of my C&R- goes in da book.
M1 carbine I bought at the flea market down the road- face-to-face, no license copy given- NOT in da book.
M1 carbine I bought before I got my C&R- NOT in da book.
M1 carbine that Dad gave me last Christmas- NOT in da book.
(Now what the hell am I gonna do with all the M1 carbines???