AR-15 Shotgun
This from "Guns America" website:
"If there is a must have product at SHOT 2012, it is the Akdal MKA 1919 semi-auto shotgun, exclusively imported in the US by RAAC. It looks like an AR-15, but it is a super-sized version made for 12 gauge shotgun shells in both the 2 3/4″ and 3″ size."
If you search by "AR shotgun", you'll find a LOT of info.
Now, was that what was used in many, if any of the articles written by ignorant reporters? Doubtful.
There aren't that many of them out there yet.