I am no expert but when I installed Geisselle SSA triggers on my LMT and Windham, I probably did it in 20 minutes per rifle. Now, I am trying to install a new Geisselle SSA trigger on my new Colt 6920 for the last hour and I just don't know what I am doing wrong. I installed the trigger and the hammer. When I cock the hammer, pulling the trigger does not release the hammer!!