Hi im new to the forum but have been in airsoft I little while.I recently tried the super shooter gears by SHS. I installed them in a dboys m4. I then noticed my air nozzle to hop up seal was completely gone all of a sudden. This gun previously worked fine. What I found was the pressed on bushing on the sector gear shaft was around .030" larger than the stock gears' bushing. This kept the tappet plate from moving all the way forward. My air nozzle was being held off the bucking lips. I took the sector gear shaft out and chucked it in a dremel. I then lathed it down with a small fine file to .150", smaller than the stock gears bushing (stock being .157 in this case). Use some fine emery cloth to polish the bushing after cutting it down. This not only fixed my problem but improved air nozzle to bucking seal better than stock. I hope this helps some people, it sure gave me the run around.