Yep, make it a carbine just like the 50 cal cause the burst makes it basically a shotgun at close range and a sniper rifle at long range.
I am a bigger fan of the machine pistol then the shotty but I think to make things even that the machine pistol be given a little more range. I think damage is fine.
Rifleman should have more uprgades for its weapons like light scope and deployable hmg etc. so it can be used reasonably !