>>54691715I was going to write my own answer but this sums it up pretty well. Guns will be finnicky at best if you're fighting multiple kinds of Pokemon, and you'll absolutely need to know what you're going up against beforehand.
I balance mine with rarity, (violent crime is low, and criminals use Pokemon as they can't be charged for assault with a deadly weapon) so you'll only see them in the hands of hunters or when shit gets REALLY out of hand and SWAT is called in.
Guns are tools, and they're not ideal in every situation. That being said, in my headcanon the average police force has access to a shitload of firepower, from grenade launchers to belt-fed machine guns to 84mm recoilless rifles