When gunpowder detonates, it creates a gaseous byproduct which expands very rapidly. The expansion of this gas is what propels the cartridge through the barrel.
As a bullet moves down the barrel of a firearm, it gets propelled by expanding gases from the ignited gunpowder. The rifling inside the barrel causes the bullet to spin, improving its accuracy by stabilizing its flight. The bullet gains speed and energy as it accelerates down the barrel before exiting the muzzle.
Rifling causes the bullet to spin through the barrel and downrange. This spin stabilizes the bullet, allowing it to maintain a straight course to the target. Without the spin, accuracy would be dismal.
Projectile expansion or projectile tumbling.
What causes it to rotate is the rifling in the barrel. What causes it to continue to rotate after it leaves the barrel is centrifugal force.
The grooves in the barrel.
There are spiral grooves engraved on the inside of a rilfe or pistol barrel. When a bullet is fired, it is forced into those grooves, which impart a spin to the bullet. The grooves are called rifling.
The spin is forced on to the bullet or shell by grooves in the gun barrel, this is to take advantage of the fact that the axis of a rotating object will tend to remain parallel, this , in effect keeps the shell or bullet in a good aerodynamic profile, without tumbling (which absorbs energy). These grooves are known as rifling and so any weapon which has those grooves in the barrel is said to be rifled.
Rifling. The barrel is not smooth on the inside. There are small grooves spiraling down the barrel which makes the bullet spin. Nearly all shotguns do not have rifling in the barrel.
Grooves in the barrel. That is called rifling.
Rifling. The barrel is not smooth on the inside. There are small grooves spiraling down the barrel which makes the bullet spin. Nearly all shotguns do not have rifling in the barrel.
Spiral grooves cut into the inside of the barrel- known as rifling.
The grooves (rifling) cut into the barrel.