Yes, 1 shot gun round can do the same if the victim is within a 150 ft range. You can take that AR and nil someone as far as 3/4 of a mile away and still make a fatal shot.
1. mass shootings do not occur at that range. and this is primarily your concern with this weapon.
2. Only 12 people in recorded history have made a shot at a target of 1300 yards or more. And the used significantly higher caliber ammunition, range finders, a spotter...etc...etc.... Your claim is beyond ridiculous. Anyone that can make a 1300 yard shot doesnt need a weapon with a capacity of more than 1 shell. as they can pick off their target at their leisure and not be seen. Think the D.C. sniper in this case. Bolt action rifle, he killed how many and created far more panic and chaos.
You know what I meant in regards to legally owned shotguns. Most states allow an 18" barrel. Less maneuverable and bulkier that an AR? Guess it depends on the "accessories" you stick on an AR. Start adding all the bafflers, upper receiver forearm mods, and other "additions", that AR is just as heavy and bulky as most conventional shotguns. Most people also stick the same 16" barrel on them.
How am I supposed to know what you meant? Sawed off shotgun is completely different than an 18" barrel. Night and day different. It isn't the weight that makes it more manueverable or not, it is the over all length. The shortest a shotgun can be legally is 26 inches. To do this you remove the buttstock. Taking away acuracy and grouping of multiple shots. Not to mention added time to rack and reaim as the gunis not in a tight shoulder position to maintain aim. The ar-15 can be about 30", less if you go pistol format but this runs into the same problems as the really short shotgun. if we leave the buttstock on the shotgun it is longer than the ar-15 and thus less wieldy around corners. Doubt me? ask military personnel.
Instead of carrying a gun when I go out, I tend to avoid any location where the potential of some kind of danger could arise.