That was awsome. I have seen cannister shot fired out of old cannons before, but that was impressive. That looks like it could take out half a battalion with one shot. I am sure they could get better patterns with a Federal Fliteconrtol wad.
My brother had the honor of being assigned to a SEAL Team while in the Navy. He was the gunnersmate and ammourer for SDV Team 1. He found some 40 mm shells loaded with buck shot in the magazine one day. Being that they were Vietnam era ordanance, he was told to destroy it. He did that the easiest and best way he knew how. At the range. He fired them from an M79 granade launcher. He had to aim for the knees because of the angle of the barrel in relation to the stock. What a spread on that though. could easily take out three men at 10 yards.
We had a 106mm Recoilless Rifle mounted on a humvee during the first gulf war. The only action it saw were a pack of hostile goats (See South Park - Volcano) in which we used a shotshell. From what I remember it was quite smaller load than that 120mm beast