Its actually not going to affect it much. First: It doesn't do enough damage for the damage reduction to be seen. Second: It doesn't have the range to begin with for the range nerf to be seen. (Not literally, the bullets have a long-distance damage drop-off, but the actual accuracy of the weapon is horrendous, coupled with the stability.) Third: The thrall perk isn't glitched, its a CHANCE of it happening. Its not a firefly copy, it is a crappy percent chance. Just like Mulligan / Rewind and 'Killing enemies returns ammo to the magazine directly'. All are %chances. Which means they can simply not perk at all. Fourth: Rapid-Fire ARs are designed for med-close to personal range. They shouldn't be used outside of the optimal range of an SMG. Sure, the bullet can hit, but its more likely it simply won't.