http://www.gatewaytoairguns.org/GTA/index.php?topic=114640.msg1126418#msg1126418Let me know if you need specifics.
Robert, if you are thinking on going with an after market gas spring, the diameter of the Enforcer is aprox 1/16" too large to fit ion the piston assembly. I've have one I want to test, but haven't found a local machine shop that will boar out the piston for me.