Guns are designed to kill people. The AR15 is designed to kill many people at one time. What other purpose does an AR15 have?
One option is to limit the AR15 to a five-bullet clip only. The clip may not be loaded when transporting the gun, and it must have a trigger lock for safety. All guns should be registered with the government.
People who buy guns for protection are only fooling themselves. Next time you are in a restaurant, look around and visualize a gunman is shooting and three people standing up to return fire. You look up and try to determine who the real shooter is? The guy with the gun, right? Which one?