PCP Stirrup Pump A PCP stirrup pump, also known as a high-pressure hand pump, is a device used to fill pre-charged pneumatic (PCP) airguns with compressed air. PCP airguns use compressed air as their power source, and the air is typically stored in a cylinder or tank built into the gun. The PCP stirrup pump is designed to pressurize the air in the gun's tank or cylinder by pumping air from the atmosphere into it. The pump consists of a hollow cylinder with a piston inside it. The piston is attached to a handle that the user pumps up and down. The pump also has a hose that connects to the gun's air inlet valve. To use a PCP stirrup pump, the user connects the hose to the gun's air inlet valve and then begins pumping the handle up and down. As the handle is pumped, the piston moves up and down, compressing air inside the pump's cylinder. The compressed air is then forced through the hose and into the gun's tank or cylinder, increasing the pressure inside it. PCP stirrup pumps typically have a maximum pressure rating, which indicates the maximum pressure they can generate. They also often have a pressure gauge built into them, which allows the user to monitor the pressure inside the gun's tank or cylinder as they pump.