We also issue them bullet-resistant vests, so no, it's not the only possible counter, but is there another ranged weapon you find more appropriate? Crossbows and long bows seem fairly unwieldy in the field.

I'm not much of a weapons connoisseur so I don't know really what's out there, but it's striking to me that the alternatives you mention are even older than the gun which as far as I know is pretty ancient. Are there any non-lethal long-range suppression technologies? Maybe smoke grenade launchers?