AA R85 A1 Wiring question

[freerider]

ok folks, I have an Army Armaments R85 A1. It recently stopped working, and upon stripping down I found that the trigger contact on the gearbox and burned out. I am looking to fit a microswitch to replace the current set up. The question I have is, that on inspection of the wiring/circuit layout, I noticed that there is a second contact that creates a complete circuit, that by passes the motor, when the trigger is released. Does anybody know why this is the case?? Is it some form of anti surge thing to keep the current down so it doesn't blow the fuse or motor?? Or have I completely misread the wiring?? If I'm right, does this mean I'm going to have to incorporate something similar if/when I fit the microswitch
Any help appreciated

[freerider]

Re: AA R85 A1 Wiring question

ok, I've wired up a microswitch, assuming the extra contact as mentioned above was a must have. attaching the battery however, whilst pulling the trigger works fine, but when released, the microswitch heats up really fast (hot to touch in a few seconds) and the fuse immediately starts glowing brightly. Pulling the trigger again, and the fuse immediately dims, but switch stays hot.
thoughts and ideas please.