SWAT 3: Close Quarters Battle (also known as SWAT3 or SWAT3:CQB) is a tactical squad-based first-person shooter, developed by Sierra Northwest and published by Sierra Entertainment for Windows-based PCs on November 23, 1999. It is the seventh installment of the long-running Police Quest and SWAT series.
This is an weapon addon/mod for Swat 3 by Mursey, It adds in the Beretta M12 Sub-Machine Gun for Singleplayer, Co-Op, and Multiplayer. This file isn't by me nor do I have anything to do with it's creation, It was originally on the swat3reunited website, Reuploaded here to get interest in Swat 3 again.
Drag the file to the following directory: Sierra/Swat3/mods, Enable via the swat 3 mod launcher and the mod will be ready for use.