How was the gun fired?

When launching, the firing pin installed in the bolt machine hits the bottom fire of the shell and ignites the propellant. The combustion of propellant produces a large amount of gas (the pressure is generally about 3×10.5 kpa), which pushes the projectile forward along the bore with great acceleration. The projectile gets the maximum velocity when it leaves the muzzle, and then flies to the target along a certain trajectory. The gas pushes the projectile forward and pushes the gun to sit behind.

A gun usually consists of a gun body and a gun frame (take a cannon howitzer as an example). The gun body consists of barrel, tail, bolt and muzzle brake. The barrel is used to give the projectile initial velocity and flight direction, and make the projectile rotate (the projectile of the smoothbore gun generally does not rotate). The tail of the gun is used to fix the bolt. The bolt is used to lock the barrel of the gun, fire the shell and pull out the cartridge after firing. Most modern guns use semi-automatic breeches, and some use automatic breeches.