In 2011, ~88% of all firearm violence in the US was linked to a handgun. You may find rifles, but they are not used very often. I also highly doubt your department has taken many, if any, M16s from criminals (or actual AK-47/AKM for that matter). I have yet to see a case where the police needed anything more than a bolt action rifle, shotgun, or handgun to handle a criminal encounter. Most of the police departments here, even the small ones of ~5 officers, have gone to load bearing vests and tactical rigs for their handguns. They look more prepared for combat than most soldiers.