Mini Cannon - The Original Pocket Cannon .30 cal, The mini cannon is a powerful .30 caliber design, which is a 5/16" steel ball, better known as slingshot ammo. It uses black powder and any firework fuses. There are two knobs to adjust the barrel up and down, for aiming, The carriage is aluminum and the barrel is solid stainless steel. The Mini Cannon is built and works exactly like the antique cannons of Napoleon’s time or the mortars used in the American Civil War.