The Bazooka – or rather the Launcher, Rock, 2.36”, M1 – was introduced by the United States in 1942, the result of a fast development by two Army officers, Captain Leslie Skinner and Lt. Edward Uhl. The US has no infantry antitank weapon at that point, and it had become quite clear that such a thing was needed. The Bazooka offered a theoretical effective range of 300 yards, throwing a 1 pound hollow-charge projectile capable of penetrating 4 inches of armor plate. The 2.36 inch bore measurement, incidentally, was chosen as the inch equivalent of 60mm, to match the common mortar size.
In October of 1943, an improved M9 version was introduced, using a magnet firing system instead of the unreliable batteries of the original. A followup M9A1 variant was adopted in June of 1944, which broke down into two parts for easier transportation, and the T90 optical sight was added in September of 1944. These were effective weapons against armor early in the war, but the heavier tanks introduced late in the war were too heavily armored for the Bazooka to be very effective – although it remained a valuable tool for attacking pillboxes and other fortified positions. It would continue to see extensive service in the Korean War, although its limited armor penetration was particularly acute in that conflict.
Note that the inert M6 rocket in the video is not being sold with the Bazooka.