The blue old normal assault rife is so fucking good and accurate. When it comes to primal vs mechanic I like these weapons this way
Mechanic assault rifle
Primal shotgun
Primal smg
Primal bow with random attachment (likely fire)
Revolver can get fucked both ways.
Those would be my choices as well. Although I haven't spent that much time with SMGs this season. Kinda have been dropping them regularly to carry around materials for my bow build.