Would you recommend a different secondary instead of the Stinger? I always seem to run out of ammo and get killed while reloading when there are multiple enemies about. (At this point I'm usually out of concussion grenades, which I usually use to give myself that extra second or two to reload).
Change the Stinger to Kap40/B23R. Change Fast Hands to Toughness. The pistol is for when you don't have time to reload......and switching to a pistol is very fast even without Fast Hands.
Hardline has got to go.......take FJ or Ghost. Ghost sounds better for you since you are a flanker. Flanking during an enemy UAV is essentially using their own UAV against them because you have the element of surprise. That also means no more wasting time shooting UAV's down and leaving yourself vulnerable to blindsides......you will be netting a lot more kills.
If the enemy is good at using nades or concussions......then you want to have a 2nd class that is basically a clone of this one but with FJ and/or TacMask. Switch classes accordingly.
I have more of a run and gun style. I don't bother with long range engagements
SMG might be better for you. Less range but more mobility, which plays right into your style. MSMC is probably best for you since you don't use a suppressor. There's a recent thread on here about that particular gun with a good variety of recommendations.....read it. If you insist on the MTAR then Stock is mandatory, the other attachment is decided by your preference and also which map you're playing.....for instance, FMJ works great on Studio, but bad on Turbine.
You didn't say what gametypes you play. The above recommendations are for TDM/KC and they come from a 2.5kd TDM solo player. Domination guidelines would be a little different......SnD guidelines would be totally different.