I am doubtful that a smoothbore OR a "straight grooved, no-twist rifling" gun barrel can achieve 4 m.o.a. with conventional ammo. I'm thinking it would be more like 18 m.o.a. at 50 yards (9" group).
That being said, 9" at 50 yards is about the best I could hope to do with an open-sighted pistol, so maybe this very short carbine will have practical CQB accuracy.
That being said, 9" at 50 yards is about the best I could hope to do with an open-sighted pistol, so maybe this very short carbine will have practical CQB accuracy.