ARES TAR 21 Trigger Replacement

[danstem]

Right got a second hand tar21 about a month ago, stick a battery init, pull trigger.......nothing! So I take it apart and have a look inside......
For a lovely gun on the outside it sure is a pain on the inside! The trigger mechanism is so long winded and complicated! First the trigger pulls a rod which is attached to a plate on the gear box. This plate rotates a lever inside which flicks another small trigger attached to a micro switch. This micro switch the activates the motor! Phew!
Having separated all the bits and figured out that it must be the small second trigger that is falling (how I still do not know) I decided to cut out the middle man and do away with all of the other bits and just make the main trigger push a micro switch.
So took it apart for the billionth time and installed a small micro switch behind the trigger like this:

Not the best job in the world but I'm not much of an expert with electronics just what I picked up on youtube.
The wires run out the back, through the battery compartment, so no cutting, and onto the motor:

Now this all works but only on full auto as the selector switch can only put it onto safety or fire. I've ordered a plug and play mosfet so that i can lock it to semi and will hopefully test it out this weekend.
Like to here your thoughts on this. Have I made a grave mistake and will my gun fall to pieces the second I get in a fire fight