This is some information on the weapons in Black Ops 2 to help people who may not know a lot about their real life counterparts and want to know more about the firearms, so here is the first list which is on BO2's Sub-Machine Guns (SMGs).
MP7 (Real; Most likely MP7A1)
The MP7 returning from MW3 with very similar stats and featuring a few asthetic differances: 4 Tan rail covers 2 on the left rail and 2 on the right, and an olive drab (OD) detached sling on the rear sling swivel. In real life it was developed in Germany by the German company Heckler & Koch (H&K) chambered for the HK 4.6x30mm cartridge. It was designed to meet NATO requirements for an armour peircing personal defense weapon (PDW). The MP7 went into production in 2001 and has been revised since it's introduction and the current production version is the MP7A1 which is most likely the version in BO2.
PDW-57 (Not real)
The PDW-57 doesn't exist in real life however has many similarities to the P90 or Project 90 developed by FN Herstal in Belgium, so we can assume that if it were real it would be called the FN PDW-57 and be developed the same as the P90. The similarities are: The PDW-57 uses the exact same unique 50 round magazine that the P90 does and the "57" in the name would prove it to also fire the same 5.7x28mm high velocity cartridge, the design is also somewhat similar such as the foregrip being of the same shape as the P90 and also the receivers being similar in appearance.
Vector K10 (Real; Actually called the Vector SMG)
In real life there is a weapon called the Vector K10 however the version in BO2 is the Vector SMG the same one as in MW2. The Vector SMG is part of a unique set of firearms designed by the US company KRISS formerly known as Transformational Defense Industries (TDI) featuring the KRISS Super V System (KSVS) which utilizes asymmetrical recoil and in-line design that chameres the recoil downwards making the Vector weapons have very low recoil. It is chambered in the .45 ACP cartridge.
The MSMC (Modern Sub Machine Carbine) in real life is an Indian sub-machine gun designed by the Armament Research and Development Establishment and manafactured by the Ordnance Factories Board. It was developed for the Indian Army, based on the INSAS family of firearms. It is chambered for the 5.56x30mm MINSAS cartridge. In BO2 it has had a RIS picatinny rail system put on the handguard for left, right and underbarreled rails, also what appears to be orange tape is wrapped around the trigger guard, the stock is also fully collapsed and unmovable in game.
Chicom CQB (Not real)
The Chicom CQB doen't exist in real life however from the design and name we can almost guarantee that it is of Chinese design, reason for this is firstly the similar trigger guard and grip as other Chinese firearms such as the Type 95 in MW3. CQB could stand for Close Quarters Combat, Chicom is also another word for Chinese Communist which might be a little easter egg by Treyarch. If this gun were real it would likely be called the CQB 25 or something similar named after the Type 25 which is another non-existent rifle in real life that appears in BO2 which seems to have a family of firearms as the QBB LMG is a similar looking LMG in BO2.
Skorpion EVO (Real; Actually called the Scorpion EVO III)
The Skorpion EVO in real life called the Scorpion EVO III is a Czeck made SMG manafactured by Česká Zbrojovka Uherský Brod (CZ-UB). It fires the 9x19mm Luger / Parabellum cartridge, however the export version which seems to be the one used in the game fires the .40SW cartridge. It is popular with US law enforcment and Police, it has a very high rate of fire which is also in the game.
Peacekeeper (Not real)
The new weapon coming to the Revolution DLC for Black Ops 2 is called the Peacekeeper, the weapon doesn't exist in real life however it has a lot of similarities to the DRD Paratus-18 (Suit Case Gun) because of the disassembly leaver at the front and the very similar reciever design, we can also see by the magazine size and cut-outs in the magazine that it may fire the same 7.62x51mm cartridge that the Paratus-18 does.
Next part: Assault Rifles