http://smallarmsreview.com/display.article.cfm?idarticles=2609#:~:text=The%20U.S.%20Submachine%20Gun%2C%20Caliber%20.45%20M2%20is,numbers%20by%20the%20Marlin%20Firearms%20Company%20in%201942-43.
The M2 article.
http://smallarmsreview.com/display.article.cfm?idarticles=4151
An article on the M42, another lesser-known submachine gun of American make.
Cool, not too many know of the M2. Unless, you’re WWII vet.