Why bullets spin

It has to do with angular momentum being a vector--which requires torque to change. See the other answers. Modern bullets are extremely precise and symmetric about their axis of flight. What they aren't is inherently aerodynamically stable. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password.

Post as a guest Name. Email Required, but never shown. Featured on Meta. Now live: A fully responsive profile. Linked 2. Related Bullet Spin. Air Density. Rifling is the practice where an arrangement of spiral grooves is cut into the inside of the barrel of a gun. But a small change to the bullet and the barrel of the gun — with no change in the other mechanics or loading procedure — increased their range to six hundred yards.

What did it take? First, it took a bullet that looked more like our modern idea of a bullet: an oblong cylinder with a rounded tip. Secondly, it took a set of grooves inside the barrel of the gun that curved like the stripes on a candy cane. This was rifling. The effect of rifling on a bullet was well-known. Even archers had twisted the feathers in their arrows to get their arrows to fly true. Early rifles, though, had a more complicated loading procedure that precluded their widespread military use.

Once rifling was integrated with old designs, everything changed. The rifling on a gun barrel twists the bullet so it spins as it flies. If the bullet doesn't spin as it flies, it only shoots straight and fast if it keeps its body exactly in line with the path of its flight. Do all bullets spin? Is this spinning of the bullet is intentional? The answer to the first question that is why bullet spins lie inside the barrel of the rifle.

If you cut the barrel of a gun, you will notice there are helical grooves on the internal surface of the barrel. Whenever the gun trigger is pulled, the primer gets hammered which creates a spark in primer.

This small explosion in the primer ignites the gunpowder in the case. The burning of gun powder suddenly generates lots of gas and high pressure gets created which forces the bullet out from one end of the cartridge. Then, the helical groovings inside the barrel exert torque and force a bullet to spin along its longitudinal axis. This spiral groovings on the internal surface of the barrel are referred to as rifling.

It is described by its twist rate which rate of spin in the rifle barrel. It indicates the distance the rifling takes to complete one full revolution. Generally, fast twist barrels are used for longer bullets while slower twist barrels are used for shorter bullets.