Perhaps more qualified door gunners could comment on the effect on aiming when your whole body is out of the side door at 120 kts
Huey gunners had no problems what so ever, mind you it was tropical weather. The set up photographed above is not fit for purpose, I'm inclined to say it's a joke introduced to impress those who have absolutely no idea, look it's got a gun. Not going to be feeding a new belt in in a hurry.