After trying many different types of ammunition, I have come to the conclusion that the best ammunition to be used in my Shadow 2 for USPSA competitions uses a 124 grain bullet travelling at 1050 fps out of a 4 inch barrel (standard barrel length for fps measurement). This results in a velocity of ~ 1100 fps out of my 4.89 inch Shadow 2 barrel resulting in a PF of 136. I have tried ammunition that is both faster and slower than this, but 1100 fps gives me my fastest split times. I will continue updating this thread as I try new ammunition, but I will be focusing on ammunition that travels at 1050 fps out of a 4 inch barrel.