autoloader

An autoloader or auto-loader is a mechanical aid or replacement for the personnel that load ordnance into crew-served weapons without being an integrated part of the gun itself. The term is generally only applied to larger weapons, such as naval weapons, tanks and artillery, that would otherwise have a dedicated person or persons loading them.An autoloader extracts a shell and propellant charge from the ammunition storage rack/compartment and loads it into a magazine or belt, if the gun has one, or directly into the chamber of the gun if it does not. It often replaces a human loader. Automation can streamline and speed the loading process, resulting in a more effective design.
With a smaller crew, the vehicle can also be made smaller inside. This reduces the amount of surface area that needs to be armored, meaning the vehicle, especially the turret, can be smaller and lighter. With a lower profile, the tank is harder both to spot and to hit.

View More On Wikipedia.org