I listened to part of the video. The old Hotchkiss is an antique not a destructive device. So no paperwork required. I am not sure you could finish building a new one before going to jail and not passing GO!
Working Gatling guns with a lot of polished brass hardware are worth $500,000.00 or more. No polished brass on the antique Hotchkiss, I did not look to see when the auction date ended. Just for grins it would be interesting to know what it sold for.
The thing the guy was calling a bolt did no locking, seems more a correct description would be a pusher/loader.

  Yeah, quite the hood ornament. An acquaintance did a very nice restoration of a Sherman tank, it had rubber treads so it could be driven on the street. I asked Fred if people gave him respect when he drove it. He said yes, everyone pulled over and took pictures! One way to clear the road.    (You need to Login

"A fuzzed exploding projectile would make it just the ticket for Cow Birds"      It would definitely thin the birds, it would also take out every tree hit. Was looking for just stunning the bird brains.