I have a Geissele hammer along with FFT trigger and sear. Trigger pull was reduced by 1 pound 13 ounces.
I’ll admit, my original intent of replacing those parts were due to chasing 922 total. The Gazeley hammer was used because of earlier FFT hammers being deformed with use. I’m not sure if the FFT hammers are still an issue but the guys Isley hammers are, as far as I know, no longer produced