[Gunny_McSmith]

yep, unscrew the tiny little screw in the middle of the grip, that should lower the motor height,

Check on youtube,they are vids on how to do that

And yes, on the SRC gen3 m4/hk416, the tabs will break if you remove the mechbox, one broke on my full metal SRC hk416, and the upper receiver doesnt even wobble at all...