M1 Thompson

The thompson was produced in the millions during WWII and was loved by the soldiers who used it because of how reliable it was. Though, it was way too damn expensive to produce that much more, and so the military was given the M3A1 otherwise known as the Grease Gun. They were seen in 1944 but didn't completely replace the thompson because of how late it was produced. I apologise for incorrectly naming this, this is probably not a M1. Searching reference images it is very rare to find a M1.