Seriously, just like Chavoda said, just cause they eventually add some sort of ordinance doesn't mean it can't be balanced.
The game is going to have ranged magic and you're worried about firearms? All of this can and will work. They just need time to test and work out issues, and they technically have all the time in the world. Remember, firearms take ammo and imagine ammo would be scarce.
I'm all for firearms, cannons, dynamite, and future technologies (ie: Model T vehicles, heck even bicycles) whenever we get around to that in the future. The game is supposed to evolve with the players so it can't stay in the Dark Ages forever. We're going to have to re-discover everything together again or choose not to. This will cause some interesting clashes between tribes that want to embrace technology and those that don't. Sounds fun to me...