Given the expansion of firearms in these house rules (especially the potential damage increase for handguns), melee and muscle powered weapons (slings, bows, thrown) are in need of a small boost in order to maintain their relative level of effectiveness.
Fortunately it's rather easily handled. Simply add 1 DC (damage class) to these weapons. No only does this result in a reasonable balance with firearms, it also produces a nicer match with how dangerous these weapons are in reality.