I got the power pack from WOLF springs. Google it, their site will come up. The PA63 is under FEG. I got the 15LB recoil spring. I changed out the firing pin spring. I don't think it's necessary but I did it anyway. The firing pin has to be raised to fire anyhow. As to it droping after it firing, ya got me on that one, I don't know if it does. I changed out my hammer spring with a 9LB spring just to see how it would do. It fires Silver Bear just fine. Some others have complained about the lighter springs lighting off certain types of ammo but I haven't had an issue. I still have the 11 and 13LB springs laying around somewhere just in case.