I did pick up the Thompson 45. It was quite heavy, may have actually been in excess of ten pounds. I'm not sure of the exact weight.
It was/is a great weapon and had a variety of clips. Bonnie and Clyde had an affection for the "round" clip which can be seen in a lot of gangster movies. Machine Gun Kelly had an affinity for it as well.
BTW - We used to refer to Vic Morrow's character on Combat as Sgt. Scar-tissue. Seems he got a Purple Heart injury every episode.