I'm personally feeling rather skeptical about the pistol grip area, especially since it looks like there's barely any space for someone's hand to get through and actually hold the weapon. I'd make the thumbhole grip a little bit larger if I were you - maybe extend this back, though you might need to extend the length of the gun:
http://prntscr.com/8u86j1The stock doesn't look very ergonomic either for proper combative use, but that's just me, I guess. Aside from what I've pointed out, this looks pretty good - 8.5/10.