"The assault rifles served a fine role. Sure, they weren't very accurate, but the hunting rifle was the accurate gun. ARs were for high fire and damage."
To be clear: I agree 100% that the assault rifles had a clear place relative to other guns ... but they did not have a clear place relative to each other. There was absolutely no difference between them, except the Chinese variant was better. The US AR had zero utility if you had a Chinese AR in your inventory (and you could get a Chinese AR very early on).
I say, create some distinction there. Give them different firing characteristics, different ammo, something. Even better, I say, just replace the Chinese AR with another gun, like the assault carbine. (I reiterate my doubt that here would be so many Chinese weapons littering DC... that gun is the standard armament of all sorts of soldiers, security guards, and super mutants! Better for it to be a special, rare thing... in fact maybe make the Chinese AR (Xuanlong) into the unique variant of the US AR... recall that the US AR has no unique model)