Forgotten Weapons, from time to time, covers larger pieces of artillery as well, not just small arms. In their most recent video, Ian and Karl fire a US M3 37mm anti-tank cannon:

The 37mm AT gun was the workhorse American anti-tank weapon at the outset of World War II. For the time, it was actually very effective against all enemy armor of the period, and the Americans mounted it to all of their cannon-armed tanks and many of their armored fighting vehicles (M3, M5 Lights, M2 and M3 Mediums, the M8 Greyhound, and the oddball air-droppable M22 Locust to name a few). By 1943, however, tank armor had substantially improved, and the 37mm became decidedly second-rate in the European theater. However, Japanese armor remained much the same as it was at Pearl Harbor, and the 37mm gun remained a mainstay in the Pacific.