A mortar.
Actually, it's a Howitzer. Mortars are not a form of cannon.
Howitzer
Morter
it is resting
A 'muzzle loader' is any firearm (or cannon) which does not have a breech mechanism and which is 'charged' (loaded with powder and shot) from the muzzle end of the barrel.
Cannon had wooden (later plastic or subber) plugs called TAMPIONS that could be placed in the muzzle to keep dirt, salt spray, birds, small animals, etc out of the cannon barrel.
Shorter barrels = less MV
Usually found with cannon, a tampion is a wooden plug used to keep foreign matter out of a cannon barrel when the cannon is not being fired.
It was actually an 8 barreled gun. Each barrel was a small cannon, and the gun had 8-12 barrels. It looked a bit like a leaf rake, since the barrels spread out in a fan. Each barrel was a single shot muzzle loading gun- but you could shoot 8 times before reloading.
A muzzle brake is a device that is designed to redirect propellant gases in a firearm or cannon. Surefire and Brownells are two great sites for learning more about muzzle brakes.
6 kg
Longer (effective) range. Longer barrels on a firearm allow for more complete burning of the propellant, which results in a higher muzzle velocity, which in turn results in a longer effective range, when compared to an identical weapon with a shorter barrel.
A horses nose is called a muzzle...x
From the face of the slide to the muzzle. Insert a dowel near the diameter of the bore until it contacts the face of the slide, mark the dowel at the muzzle, withdraw, measure.
There have been more than 2 dozen DIFFERENT 20mm cannon (search 20mm Wikipedia for examples). These used different shells, and had different barrel lengths, and so have different muzzle velocities. The 20mm used by the US and Allies during WW II had a muzzle velocity of ABOUT 2800 feet per second.