I put quite a bit of effort into tuning my PO-7 for a light DA trigger pull weight and a least creep SA carry level pull weight. My combination is the light trigger return, firing pin return,and firing pin safety springs, a 13# mainspring, the stiffest of 3 red sear springs,a longer firing pin spring, a CGW hammer,and a 15# recoil spring - yields 7# DA and 4# SA trigger pull weights. The CGW hammer makes a big difference in SA trigger pull feel. Also, I trialed the the dark, natural, and red sear springs (3 Each) and found about a 3 oz pull weight variance in each color - could tune the SA pull weight between under 3# to 4#. The oem hammer makes for a very soft SA break feel compared to the CGW hammer. I don't use hard primer ammunition but works fine with soft primers.