i was watching the military history channel today and i saw a marine in ww2 with an m1 carbine that had a muzzle brake on it. i can understand a flash hider but i dont see the purpose of a muzzle brake on an m1 carbine.
Could you post a link or a photo? I can't recall any WW2-era USGI muzzle brakes for the M1 Carbine off the top of my head.
There was a post-WW2 issue M1 "Recoil Check" (i.e. muzzle brake), which was used in the Korean War. It was designed to allow the M2 Carbine to be a little more manageable on full auto. It could have just been Korean War footage sloppily reused in a WW2 documentary.
However, the T3 carbine, which was used in very late WW2 (specifically Okinawa), included a conical flash hider to keep muzzle flash from interfering with the infrared optic.