For this week's #ThrowbackThursday, we're heading back to the early Twentieth Century to learn about one of the most well-known firearms of all time: the M1A1 Thompson submachine gun. This simplification of the original and famous "Tommy Gun" of the Prohibition Era was designed to for inexpensive and fast production, which was a real boon for the Allied forces in World War II. Check out this video from American Rifleman's Mark Keefe and NRA Museums' Phil Schreier for more of the fascinating history of this military arm.