Believe it or not, this is not a fictional firearm. Thompson Firearms really did try to make a version of the gun in .30-06. Only one prototype was ever built. It takes BAR magazines and has a unique "expanding" bolt to try and make the locking system work in rifle cartridges.
Thank you Volks for modifying the thompson model into this abomination.
Changelog
V1.0.0 -- Initial Release