Jeez, I don't think this artist knows the difference between an AR10 and 15.
Actually it looks closer to a 50 cal!
EDIT: Apparently this site must have been infested with liberals who hate the truth when I wasn't looking. The proportions on the gun make it clearly not an "AR15". Yeah, that's downvote worthy.
The magazine is too long for anything you will find an "AR15" chambered in, the barrel too thick, and even considering that the girl is too small, the gun is way too big.
The proportions of the girl herself are also really off.