The Mag-5 is a powerful revolver with a large, thick barrel. The Mag 5 has seven rounds as well as the exact same power and accuracy as the Desert-5. In terms of performance, the Mag 5 possesses long-range accuracy and high damage capability, making it useful when facing with a few enemies. The Mag-5 can kill un-armored enemies with two shots.
In singleplayer and Co-op, the Mag-5 is mostly used by snipers.
Oddly, the gun for the symbol of the Mag-5's trophy is a Para 9.
The Mag 5 is on equal footing with the Desert-5, althought this is unusual,seeing as how the Desert-5 fires the .50 AE round, while the Mag 5 fires the .357 Magnum round, which has only half the power and accuracy of the much larger and more powerful .50 AE round.
It is one of the three weapons to be specially found and used at Chapter 5, the others are the M9 and the Para 9 (Commonly found the skull enemies with the red eyes and laser sight, while the other weapons are found at the enemies without the sight.)