AB-50

In a world where bio-weapons run amok, weapons, even small arms have evolved. By Resident Evil 6, the AB-50 was a small arm of choice for several major players during the C-Virus outbreak, including Ada Wong. The machine pistol is also used by J'avo, infected by the C-Virus in many parts of the world, including China. In the Mercenaries mode of the game, Ada wields this gun, but Helena Harper in costumes 1 & 2, as well as Piers Nivans costumes 1 & 2, also have this in their loadout. The gun is also used by the DLC character Rochelle from the series Left 4 Dead. Judging from the look of the round, the AB-50 most likely fires the 9mm round many other guns fire nowadays, within a 50 round magazine.