Information on Mossberg bikes is hard to come by. I do know that they got into the business by purchasing the Stelber bicycle factory (Rollfast, Iverson, Hawthorne) - and very quickly from that point moved onto greater things (ie. they dropped the line of kiddie one piece crank bikes and moved up market). I think that would have been some time around 1974/5? They decided not to continue doing business with Rollfast, and Rollfast subsequently sourced bikes from AMF before the brand name dropped off the face of the planet entirely.

I have no idea when Mossberg ceased making bicycles.