But the problem with the urban assault argument is the nature of the scenario itself. If you have a small room filled with just a bunch of targets, then go ahead, an AA-12 works great. But so would an M67, which is cheaper to produce.

Now in the more common variant, there are civilians in the mix. This is more or less why the M4 was produced: it took the power and accuracy of the M16 and condensed it into a smaller, more maneuverable firearm, to be used in CQB situations. With the M4, you can aim and fire accurately and quickly without injuring any civilians. With the AA-12, you either have shot, which is just shit for that situation by nature. If you’re carrying around slugs, then that’s a little better, but given the caliber, it could take 2-3 shots to actually knock a target down due to the drugs they’re given. The AA-12 either has a 20 round box mag, or a 50-round drum. The rate a fire would chew through the 20 round almost instantly, and if you’re using the semi-auto option, then why not stick with the M1014? A Marine is NOT going to be carrying around a 50-round drum and extra ammo, and also have a carbine or rifle. The AA-12 is a great show gun, but it is not that great for combat. Anywhosit, all shotguns are being rendered obsolete by the MasterKey anyway.