What operating system does a semi-automatic shotgun utilize?

A semi-automatic shotgun typically utilizes a gas-operated system. This mechanism works by redirecting a portion of the gas generated by the burning powder when a shell is fired back into the action of the shotgun, which cycles the action and loads the next round. This gas operation is efficient and allows for a relatively reliable cycling of different types of ammunition.

In contrast, pneumatic operation refers to systems that use pressurized air, which is not common in shotguns. Electric operation is generally associated with firearms or air guns designed to use electronic components for cycling, which is also not applicable to traditional shotguns. Spring-operated systems rely on the energy stored in a compressed spring to cycle the action, more typical of airsoft guns or traditional pump-action shotguns but not semi-automatics. The gas-operated system in semi-automatic shotguns is favored for its effectiveness in managing the energy from the discharged round, making it the predominant operational method for this type of firearm.