Another vote for had one, let it lapse.
I had the renewal all filled out, but neat C&R guns were winding down, many retailers were dropping their discounts. The only things I ever logged were CMP rifles. Now, as others have said, you get to pay caviar prices for clapped out shit that's been rusting in the bottom of a Ukrainian salt mine for the last 60 years. Most 01 FFLs won't honor the >50 yrs aspect on older guns either, at least in my experience.
From my memory:
- Bound book could be destroyed the day after your license lapses. If you're renewing, it obviously needs to be contiguous.
- Bound book has to contain any C&R firearms in your collection, even if they were acquired prior to the license or via a typical transfer, so if you destroyed yours and got a new license, you'd have to re-enter everything This was wrong and I am a bad person for posting it
- ATF doesn't get free rights to visit you whenever they want, can be done at their offices at your convenience. The "if they suspect a violation" isn't some grand loophole. If your local police suspect you're dealing drugs, you're going to get a surprise visit too. Don't manufacture machine guns in the garage and you'll be okay.