How does a semiautomatic gas-operated AR-15 style rifle function?

A semiautomatic gas-operated AR-15 style rifle functions by using pressurized gas tapped from the barrel. When a round is fired, some of the gas produced by the ignited gunpowder is redirected through a small port in the barrel. This gas travels through a tube and pushes a piston or directly impacts the bolt carrier group, cycling the action of the rifle.

This method of operation allows the firearm to automatically eject the spent casing and chamber a new round from the magazine after each shot, while still requiring the shooter to pull the trigger for each individual shot. The use of gas operation is efficient and helps to manage the energy produced during firing, ensuring reliable cycling of the action.

Using a crank handle, operating on blowback, or manual cycling of the action are not relevant to the specific functioning of a gas-operated system, as these mechanisms pertain to different types of firearms or action designs.