Since this is an ares gun... Im pretty sure that this gun has a microswitch. I have worked on them and they suck! With my experience this always happens with ares guns. Your problem is the proprietary cut off lever. The only way to fix this is to get a new regular TM style cut off lever, trigger contacts and then figure out how to put them in the gun. If it is impossible to put them in there...it most likely will be...then you will have to add a new gearbox shell to your list. Sorry for this big explanation but I just wanted to share my experiences. 