A rifled cannon can shoot approximatly 500 yards. The rifled cannon is a great weapon. I advise you to use it(if you have one) in a space between 600 and 700 yards.
cannon
Anything 20mm or larger is considered a cannon - an entirely different class of weapons from small arms.
20mm cannon
Slug rounds are infamous for not being good at piercing armor. They may have a high weight, but they fly at a very low speed, meaning they don't have as kich power as you might think. So, with that said, no, a 20mm slug could not punch through titanium.
Cannon is a term typically used to denote a weapon with a bore of 20mm or greater.
Since the Comanche program was cancelled in 2004, I'd say the Apache. In theory? No contest: the Apache carries a 30mm cannon, while the Comanche carried a 20mm cannon. Both aircraft are designed to be resistant to 23mm cannon fire, so an Apache could shoot down a Comanche but a Comanche couldn't shoot down an Apache. Both birds can carry the Stinger antiaircraft missile, but the cannon gives the edge to the Apache.
No, you cannot shoot a squirrel out of a cannon as a substitute for a cannonball. The squirrel will disintegrate very quickly.
No. But where you shoot it, what you shoot it at, or where the projectile goes can be.
It was considered a scaled down - or miniature - version of the Vulcan 20mm cannon.
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.
All cannons are guns, but not all guns are a cannon. A cannon is typically a large diameter firearm, NOT fired from the shoulder or hand, and fires in a direct fire mode (barrel angle less than 45 degrees to the ground. For instance, the .50 caliber machine gun is a gun, but the 20mm cannon has a larger bore diameter, and is not fired from the shoulder. During the first World War, there was a 20mm anti-tank rifle. Despite the size of the bore, it was fired from the shoulder (OUCH!) and is not a cannon. With some artillery peices, those that can only fire in a direct fire mode, they may be designated as guns, to distinguish them from howitzers, which CAN shoot high angle fire.