My Shockmaster®

Instructions for E-Z High Pressure Pump

A high pressure hand pump especially designed for air filling of Shockmaster Stocks. May also be used on JS Aircushion and modified Hydrocoil. This design is meant to work with schraeder (automobile-type) valves. This pump can be rebuilt: Both the piston and built-in no leak schraeder adapter have replaceable O-rings and seals.

E-Z HP Pump


Remove the access plug in the recoil pad. Insert the E-Z pump through the hole and thread it directly onto the recoil reducer valve until the gauge registers pressure. It may be necessary to hold the piston between the thumb and forefinger in order to stop piston from spinning. (Do not use the E-Z HP Pump with the chrome valve extension provided with your Shockmaster, they do not function properly when coupled together.) Pump to desired setting. Unthread pump. The unit should not lose pressure upon removal. An audible air loss is from the hose and gauge, not the recoil unit. Just set-remove-and Happy shooting!

Please note: Any time you thread the pump onto the schraeder valve you capture air out of the recoil reducer in order to pressurize the pump and gauge, therefore the pressure reading will be less than the pressure that was actually in the cylinder when you started. For this reason you can not use this pump or any pressure gauge to check the cylinder air pressure without significantly reducing the cylinder air pressure in doing so. For example: I pump my Shockmaster up to 110 lbs., unscrew the pump and hear the (normal) audible air loss from the pump and gauge. I then, screw the pump back on and find that the gauge reads lower pressure. This is normal and is not an indication of any malfunction. The pressure loss is because air went into the pump and gauge, therefore lowering the pressure in the cylinder. If the schraeder adapter begins to leak after repeated use, unthread and flip the grommet to expose the "fresh" side. Replace only after both ends are worn. Replacement parts can be ordered from G-Squared.