Cliffton,,,,,
You can in fact add quite a bit of FPE to an SS by swapping the 12 inch barrel with a longer one. Matter of fact I remember reading that a standard 12 inch SS .22 cal barrel will give you 26 FPE (depending on the pellet) ,,,,,, if you install a 24 inch barrel your FPE will rise to around 42 FPE (again, depending on pellet). This increase is just by changing the barrel. You don't have to mess with the hammer weight or anything else,,,,, one of the things I like about the Air Force "platform" is the versatility :)
Jeff