So I managed to resolve everything! Thanks to everyone who contributed in this thread!
The problem initially was the motor needed to come down a bit as the new MIAD grip had it way too high. Then what was happening was that it wouldn't fire the nozzle however the spring was cycling. I fixed this quick as I noticed that the tappet plate wasnt connected to the nozzle.
Then I noticed that it still wasn't firing BBs. I opened it up one last time, watched a video on youtube of what a gearbox looks like when it cycles (as I obviously couldn't watch myself) and I noticed that the sector gear wasn't engaging the tappet plate. I soon fixed this by just turning the sector gear to 1 o clock.
Voila...I can now FINALLY fire my KA M4 for the first time.
Here's a picture of what she looks like...
Thanks again to you all!