12 ga Belt Fed AR Upper Posted March 24, 2016 in AR-15, Shotguns by Nicholas C with 25 CommentsTags: 12ga, Belt Fed Sure there were some people trying to convert AR10s to shoot 12ga. Then there are the AR style 12ga shotguns. Now someone has made a beltfed AR upper that shoots 12ga shotgun shells. Just need to iron out the kinks.