Ive not seen any topic around the perks anf attachments for online gameplay, just Zombies. well heres a nice little guide on what to use on a few guns which i really favour.
Assualt Rifle- I usually tend to stay away from these, but the STG is quite a good gun. Low late of fire, but accurate and moderatley powerful. I find using, Appurture Sight Bandolier Double Tap/Stopping Power Deep Impact
Sub Machine Guns- The thompson is a really nice gun for using at close range, but when using it at a distance its acuracy really lets it down in my opinion. i use, Round Drum Bandoiler Stopping Power Extreme Conditioning
MP40- Probably the best gun in the game, it has a nice fire rate and is very powerfull. Many like to use double tap or juggernaught ( Juggernaught is now widely used because its so much easier to kill others) and double tap because of the power the gun already has. i like to use Round Drum/Silencer Bandoiler Stopping Power Extreme Conditoning
Machine Guns- Fail, enough said. lol
Sniper- Its got to be the spring field, i know the last one is quite awsome, but for me i love the bolt action signle shot rifle. its more precise in my opinion and can be used with juggernaught and gets plenty of one shot kills. but obviuosly lowers its power. Scope Bettys Stopping Power Deadly Silence
Well all views are welcome - either criticise what ive said or agree and add futher to it, either way its all fun