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From the Halo Universe.

The Assault Rifle from Halo Reach, and the forerunner of the MA5B and MA5C seen in Halo: Combat Evolved and Halo 3 respectivly. Also known as the MA37 within the UNSC Army, and the MA5A elsewhere.
The MA5 premeired most of the features that are now standard on UNSC assault rifles.
by Orcaman February 07, 2012