.30 Carbine machinepistol is certainly a concept
That is the Kimball pistol, and it is
FUCKING TERRIFYING, even more that they built a select-fire one, which I had no idea about. The barrel is fixed and the little slide is unlocked, what it has is a little annular ring cut in the chamber which the brass case will expand into, and which has to be straightened out as pressure pushes the case back against the breech face.
For
.30 US Carbine
Here's some patent drawings.
The normal semi-automatic pistols were scary as fuck alone because there's just a small plate retaining the slide to the frame, which gets hammered at high speed every time it cycles. Every Kimball pistol ever made exhibited horrendous reliability and pants shitting peening on this retaining plate, leading to urban legends about the slide breaking free and lodging itself in someone's eye socket. The owner's manual warns explicitly against using steel cased ammunition.
More shots of the select-fire one which I found
here after quick Googling. I don't know if the cool dude with the mustache is John Kimball himself, but the hearing protection is gonna be vital. What are we looking at here, 2" or 3" of barrel for .30 Carbine? A Ruger Blackhawk with an 8" barrel is already a loud and blasty monster with this cartridge, now picture this snubnosed deathtrap blasting away at who knows what RPM, possibly in excess of 1000.
Why not
A slightly saner concept, the Bushmaster Arm Pistol. The grip and trigger can be swiveled around, I think the idea was that this supposed to be like a survival+combat weapon for downed pilots. These exist as semi-automatic pistols, and as
select-fire ones. These pistols formed the bases for the more conventional Bushmaster "Assault Rifle" (used in marketing even for the semi-auto ones), and they look even less elegant here.
The Arm Pistols here have those old Zytel AR15 magazines, which were not very great. The most notable and memorable thing about the Bushmaster Assault Rifle, apart from being ugly, is that they were to be used in what's known as
Operation Red Dog, which was an attempt by a small white supremacist militant group to try to conquer the island nation of Dominica, by the means of a boat, some dynamite, and some of these rifles.
Someone snitched to the feds and the entire thing fell apart before it could even be executed, leading to various amounts of prison time and at least one suicide. One of the sentenced conspirators was none other than Don Black, the future founder of Stormfront.