US Patent 9464860 Shotgun simulator

A shotgun sound simulator comprises an elongated enclosed tube defining a combustion chamber into which an ignitable mixture can be combusted. The tube also includes at least one baffle and an open end having a smaller diameter than the tube. The open end permits ignited gases to escape. By controlling the ratios of the tube diameter (TI), the outlet port diameter (OP), baffle opening diameter (BH), combustion chamber length (CC); and the distance from the combustion chamber to the outlet port (RC), a simulated shotgun sound can be produced upon combustion of a gas in the combustion chamber. Conveniently, the outlet port can be made to receive a training bumper that is launched when the gas is ignited.