hmm.. this may sound really weird, but I was just looking at mine, and noticed the gearbox has 4 threaded holes. I dont have much V2 gearbox experience but on my A&K masada it only has 2 holes. Now, the holes didn't seem to line up absolutely perfectly with the grip. So I switched which 2 were being used to hold the grip on, and the selector is smooth as butter again. Theory: maybe that was twisting the gearbox a bit?
I'll play around with it some more.. The next 2 things I can think of to try are either mill down the blade on the selector switch, or swap the bearing there for a bushing and mill it down so it doesn't stick out past the outside face of the gearbox.
in the meantime, I figured I may as well order one of these too:
http://www.airsoftparts.ca/store2/in...oducts_id=2136