My buddy got three Stock2, at first it was problematic with SB, Win, and CCI primer, however after a lot of tweaks, with a combination of PD firing pin, titan hammer, PD 13lb Hammer spring and PD TRS, his gun now run flawlessly. The DA is about 6lb and 2lb SA now, with little to none noticeable stacking. BTW, none of his s2's had TRS problem.