damn, thats cool ross, needs more angles though.

About the proportions, I know what your saying, but I think it has to do with the way the front of the gun looks, I like it, if anything either the front of the gun seems to big, or the back seems to small, thats about all I see thats wrong, I'm not a weapons expert though. Either way I love it.

EDIT: If theres a bi-pod on it actually I'd consider trying to scale up the rear of the gun a bit more then.