Oh, yeah . . . a Lott lock. Have one on my Pedersoli NW gun.
Did sort of a failure investigation in the '80's, Indian made blunderbuss imported by a reputable firm. Shooter used an empty shotgun shell full of black powder + newspaper wadding to make some noise. Fortunately when the breechplug blew out it missed his head, no physical injuries.
The Indian steel breech plug was too small as-threaded. Although it had blown out, only the very tips of the fine threads were smeared over. Fine threads. I could thread the plug back in easily, and it did rattle.
One NEVER uses, or should never use, fine threads in brass. Need to use a coarse thread, for strength. A boring engineering thing.
I imagine it would be best if the "winner" did not shoot it.