SMGs are confirmed for infiltrators. They will be a primary weapon available to all classes and are meant for close range combat. The NC SMG shown had 25 bullets per magazine (likely with 167 damage per bullet), the TR version 35 (likely with 143 bullet per shot). The VS SMG wasn't ready to be shown yet. Source for this is Friday Night Ops - Episode 17 Apparently the devs think that giving infiltrators SMGs isn't going to create any problems like shotguns did in beta. With that there isn't any reason why auto scout rifles should be worse than carbines.