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Types of Cannons
Cannons have been around since the Middle Ages. Since that time, cannons developed from sled-drawn tubes to the high-tech pieces that armies field today. There essentially two types of cannons: smoothbore and rifled. Smoothbore cannons are the oldest examples of artillery. They are usually cast iron or brass and the inside of the barrel is smooth. These types of cannons fire a ball. Rifled cannons have circular grooves cut into the inside of the barrel and fire a projectile or shell. The circular grooves cause the shell to spin in the air, which allows it travel farther and have more accuracy.
How Smoothbore Cannons Fire
When firing a smoothbore, muzzleloading cannon the first thing that happens is sponging the barrel. A long pole with a large wool swab on the end is dipped into a bucket of water. The swab, being 1 inch smaller than the barrel, is placed into the barrel and pushed all the way in to the end. It is turned a few times to ensure the barrel does not have debris left from the last firing. It is then removed. The next step is to insert a cartridge, which is bag of black powder, usually made from wool, cotton or flannel. Varying the amount of black powder changes the range of the cannonball. The cartridge is rammed into the barrel with a rammer. A rammer is similar to a swab, but without the wool on the end. The shot, or cannonball, is strapped to a sabot, which is wooden block that keeps the cannon ball stable inside the barrel when it is fired. The rammer is used again to push the sabot and cannonball up against the cartridge. A priming wire, which looks like an ice pick, is pushed into the hole, or vent, at the back end of the cannon. This creates a hole in the cartridge, exposing some of the black powder. The vent is then filled with black powder. Once the cannon has been aimed, and the order to fire was given, a lighted fuse is place over the vent. This ignites the black powder in the vent, which then causes the cartridge to explode, which pushes the cannonball out of the barrel. When the black powder is ignited, it burns quickly, causing large amounts of hot gases and solids to explode. This explosion pushes the cannonball out of barrel as gases and solids attempt to escape from the barrel. Cannons like this can be fired once every 8 to 10 minutes.
A breechloading cannon works a little differently than a muzzleloading cannon. A breechloading cannon does not load from the muzzle, but from the breech, which is an opening at the back of the cannon. Most breechloading cannons have rifled barrels and fire shells, not cannonballs. Unlike the muzzleloading cannon, the shell or projectile contains the powder and bullet in one piece. There is a primer in the flat end of the shell that is struck with a hammer, or firing pin, that ignites the powder inside the shell. The breech is opened at the back end of the cannon and a shell is placed inside. The breech is closed and locked down, usually with a turn of a handle. This places the firing pin on the primer of the shell. The order to fire is given and a lanyard is pulled, which causes the firing pin to strike the primer in the shell. That causes the powder to explode, which pushes the bullet out of the cannon. The breech is then opened and the empty shell falls out and a new shell is placed inside. Cannons like this can be fired every couple of minutes.