Check out this custom MPX Rifle that operates on gas operated loaders, self-loading firearms, in which the recharging process is triggered by the gases of the propellant charge generated during the shot, are designated as gas pressure loading devices .
After the shot has been ejected, gas is removed through a bore in the barrel wall. With the energy of this high pressure gas, the shutter is unlocked and opened, the empty cartridge sleeve being ejected. When the closure is closed by the closing spring, a new cartridge is guided into the cartridge bearing.
The brethren Clair from St. Etienne were the inventors of the gas-pressure machine. In 1889, they were able to patent a design of a gas-pressure loader with a gas sampling bore and gas pistons under the number 49100 in Germany. Other inventors such as Pitcher and Dewhurst (England) and Un (Sweden) developed similar systems whose gas sampling bore is similar to the modern Desert Eagle gun near the cartridge bearing.