Here's the thing about SMGs:

Hipfiring = effective but reload often (even with damage boost, I add)
ADS = effective but reload once per kill

Assault Rifles:

Hipfiring = slightly effective, probably reload once per kill
ADS = effective but 1.5 (2 with damage boost) kills per reload

And that's it in a nutshell. Maybe the damage boost should affect SMGs less and ARs more, I think it's 75%+ damage? However, as they are the game is still fairly balanced.
I refer to my previous post, SMGs are great in this game because the situation usually calls for one. ARs beat them easily when the sections of map open out.

I do like how everyone talking about the carb 9 it is a great gun with damage but I can only take one about 1 person pre clip I love the ump cause I can take out 2 from a distance and the cross is great for close fire , the Tampa can [censored] you in a second , I think all the smgs are balance , even gun is for a different type of game play. It just people always try to go with the gun with the most damage. try a different gun other than the carb 9. If I always a med and I was play a short halls ways map with almost no big opens I would use my cross or the Tampa for the fast and great hipfire. People just have to learn with gun is the best in every situation

even though im mainly a light engineer and rely fully on my TDI Super V(ector) aka KROSS (muzzle brake, speed sling, drum mag, enhanced iron sight)
i must agree, with my weapon buff i could potentionally wipe out between half and the entire enemy team WITH ONE MAG,
yes hates, this is under nearly perfect conditions, but it does happen often on maps like SEC Tower and CCity.
all stats, besides drum mag (which i love, but gives me 70 shots per mag which is insanity),
all other stats seem to be what they should be, pretty low dmg, high fire rate, medium accuracy, pretty low range,
yet i can easily take a few enemy out from behind and usually can take 2 from upfront.

Even though it is probably my greatest strengh, i agree a nerf of some kind needs to be in effect,
no more drum mags and worse hipfire would be a way to make it alot more far,
cause i can just stand across the room and hipfire my entire mag into a few guys and blast time with perhaps only 5-10 out of 70 bullets missing target.
full buffed heavy cant even stand half my mag, which would leave me to take down another 2-3 lights or 1-2 meds

No, but it's hardly a unique design. It looks a lot like a SCAR, and they (like pretty much every assault rifle in existence) have selective fire. So...a SCAR set to semi-auto = Rhokstedi.