Yes, a 26" barrel with 3" chamber will fit. As Fred said, the barrel may be able to use 3" shells, but the receiver, well actually the ejector, is set up for 2 3/4" shells. In order to use 3" shells, the ejector must be set back (simply order a 3" ejector, and rivets) and knock the old rivets out, put in the new ejector, re-rivet, polish and blue.