Newest addition to my WW2 US martial arms collection is this 1943 Inland M1 carbine pictured with my 1945 Springfield Armory Garand for size comparison...
Question: Do you know what year they started putting the bayonet lugs on the M1 carbines? I was under the impression that they weren't added until the end of WWII.
The bayonet lug on the M1 carbine is part of the barrel band, not the barrel itself. The barrel band can be swapped to a WW2 era one and thus no bayonet lug. The barrel band with the lug (I believe it's known as the type III) was developed in 1944 but it is doubtful very many (if any) reached the front lines during WW2.
This photo shows the two main types of barrel bands: