I thought form 1 limited you to the exact barrel that you file it with? Example; if I have a regular ole AR15 that I want to SBR, but I don't know if it will be a 10" 300BO, or a 8" 5.56, or if next year I want to add another upper to use on the registered lower, etc. I thought that Form 1 doesn't allow you to have this flexibility, and to have that flexibility you needed to register with a form 4 stamp??
Free men own guns...Slaves don't!