Flak Jacket
Warlord
Second Chance/Tactical Mask
(All Pro of course)
M60 w/ Grip & Extended Mags
Strela
Semtex/Frag
Concussion
Claymore
This is probably the most beast class I've been able to come up with. The M60 is a 2-3 shot kill on Core, 1-2 Hardcore. While it has some nasty recoil, Grip helps with that problem, and it's fairly easy to learn how to control. Slap on Extended Mags with it and you never have to reload as well (200/0 on spawn).
Since your slow moving you need to post up with it a lot, or else you'll lose on the draw unless lag is working in your favor. That's where Flak Jacket comes in, for obvious reasons.
As far as the 3rd perk goes...I tend to go with Second chance more out of preference. But if you choose Tactical Mask, it will be almost impossible to move you.
Now the main argument against Second Chance is "If I kill you, you should stay dead. Not Fall and pull out a pistol." Granted the only time I hear this is if someone gets killed by a Second Chance user. But look at it this way...If you get killed by someone in Second Chance, you deserve to die just as much as they did. Because you just got killed by someone who is practically stuck where they are, who only has a pistol...and here's the kicker, HAS ONE HP. quite literally anything can kill someone in Second Chance. But if that person has good aim and a nice trigger finger they can ideally take 1-2 sometimes 3 people down with them.