When you unlock the Specialist bonus (8 Kills in a Row, or 7 with Hardline)...
You unlock ALL the Weapon Proficiencies, which include kick, speed, range, stability etc.
However, when you are a SMG user, you also unlock rapid fire!
What is so cool about that? Well, you could technically have 3 attachments, just slap on a Red Dot Sight, Silencer and when you get the Specialist bonus...you have all 3 attachments!
![Smile :)](./images/smilies/icon_e_smile.gif)
I run with, MP7 Extended Mags + Silencer...Sleight of Hand, Assassin, Dead Silence.
2: Stalker 4: Extreme Conditioning 6: Scavenger.