With a TTI reduced power hammer spring I had several light primer strikes (FTF) using Fed or Win cheap bird shot (about 100 rounds). This was several years ago. I also installed the FFT trigger package (trig, hammer, dis-connector) at the same time. I went back to the OEM spring. I did like the pull with the TTI spring - definitely reduced weight. Felt good, but the occasional lack of a bang made it a no-go for me.
I just notice that FFT uses Wolf springs...I wonder if they are better than TTI's springs. Anyone?