To be thruthful I am not sure about this, but if they made the game as realistic as possible then you must shoot all rifles at the greatest distance possible. All rifles have different velocity, shock power, and effectiveness at certain distances. If the weakest rifle can one shot kill at 30 meters then it would not make sense to test them at 30 meters if you get my drift. So I would suggest going on cliffside or even downfall and shooting all the way across the map for a true test. Once again Treyarch is a shit company and I am not sure that they took any of this in to consideration, why would they when they can't even get a map correct, right?