Canister is probably one of the most horrifc yet highly effective types of ammunition to be used agaisnt an approaching line of soldiers. Canister is essentialy a tin can filled with over a hundred .69 cal lead balls and a wooden sabot at its base.
It’s a type of close range artillery projectile round fired from a smoothbore cannon. A poweder charge (gunpowder) would be inserted first into the cannon barrel follwoed by the canister. The basic concept is that when fired and upon exiting the bore of the cannon the lead shot spread out in all directions with the idea of impacting as many soldiers as possible (basically in one shot). This was highly effective at repelling an attack, tearing huge holes in the ranks of advancing soldiers. It was not uncommon to load the cannon with multiple “loads” of canister to maximize the devastation on the approaching enemy. The picutre above is a borrowed image of a nonfired origianl example of canister. The video below is one that I took of a piece that had been lying on the bottom of a river since the war nearly 150 years ago!!!