I have noticed that quite often weapon damage seems to drop radically when opponent is very close to you. By radical I mean that you get like 30-50% of normal damage. I have seen this mostly with rifles and shotguns. Considering that bullet has largest kinetic energy when it leaves barrel, damage should be increased when shooting from really close range. At least based on normal physics. And for shotguns pellets spread the further away they get from barrel, so in their case too damage should be maximum from close distance.

When opponent is practically staring into my rifle barrel (I always try to shoot to head in order to save ammo which is too rare in the first place) it should not get that big benefits from the game, right?