How does a World War 1 machine gun work?

Answer 1

Most WWI machine guns functioned exactly the same as today's automatic and semi-automatic weapons. There are two main types of machine guns - gas operated and recoil operated. Most modern and the most widely used WWI models (Vickers, or Maxim guns) were gas operated.

A shell is fired, causing its propellant to explode and turn into rapidly expanding gas. This drives the bullet down the barrel. Very near the end of the barrel there is a little hole, called a gas port. After the bullet passes over this hole, but before the bullet exits the muzzle, the rapidly expanding gas rushes down this hole and back through a gas tube, where it also pushes a piston. This piston is connected to the action of the gun, and when the gas causes the piston to travel back it works the action of the gun, causing it to extract and eject the empty cartridge case. Then springs push the action forward again, picking up a new, loaded cartridge on the trip forward. The new cartridge is seated in the chamber and if the gunner still has the trigger depressed, the firing pin strikes the primer in the base of the cartridge causing this next shell to fire. This continues as long as the gunner has the trigger depressed, or until the gun runs out of ammunition. Then a new belt of ammunition must be inserted, and the charging handle of the gun pulled back by hand. This pulls the action of the gun back, then when the handle is released the springs push the action forward to pick up and seat the first cartridge of the new belt, and then the gun is ready to fire again.

Because the rapid firing causes the barrel to get very hot, many WWI machine guns had a water cooling jacket built around the barrel. During heavy firing the water could be boiled away. Continued rapid firing without some cooling might warp the barrel, rendering the weapon unusable.

Answer 2

A World War 1 machine gun typically used a gas-operated mechanism. When the trigger was pulled, it released the firing pin, striking the primer of the cartridge. As the round detonated, it propelled the bullet forward, and the expanding gases moved the barrel rearward. This movement unlocked the breech, allowing the spent cartridge case to be ejected, and a new cartridge to be loaded and fired in rapid succession, providing sustained automatic fire.