M392 DMR

"The single-shot DMR fits somewhere between the sniper rifle and the battle rifle. It's deadly at range, but a quick trigger finger and careful aim assure that even at medium to short distances it packs a punch."

- Game Informer

The M392 Designated Marksman Rifle, commonly abbreviated as the DMR, is a battle rifle used by the United Nations Space Command.

Background
Although it saw more widespread use throughout all branches of the UNSC prior to 2548, it has since been superseded in use by the BR55 in all branches but the UNSC Army.

Design Details
The M392 Designated Marksman Rifle is an air-cooled, magazine fed, gas-operated select-fire bullpup rifle that fires 7.62x51mm ammunition. It takes a twelve round detachable magazine, similiar aesthetically to the BR55. The weapon holds a mounted scope capable of 3x zoom and possess a fire selector switch located above the grip of the weapon, and a magazine release button, which is located directly above the magazine housing, behind the trigger. The weapon has two ejection ports, one on the left and right hand sides of the weapon respectively, so that a left or right handed shooter can fire the weapon.

Trivia

 * Stamped on the comb of the rifle are the words ARMALITE MG UNSC. This is possibly the manufacturer or a reference to real-world manufacturer ArmaLite Corp.
 * The designation of this rifle model as a "Designated Marksman Rifle" would seem to indicate that it was designed for use in squad-based combat, and not as a dedicated sniping tool. Designated Marksmen function in U.S. military fire teams to provide long-range support to their teams. This contrasts with Snipers who operate in small sniper-based squads and received more specialized training.
 * This weapon's semi-automatic functionality is similar to the Battle Rifle in the 2003 Halo 2 E3 Demo.
 * This weapon is aesthetically and functionally similar to the real life Kel-Tec RFB and the IMI Tavor, all the three weapons sport the bullpup configuration, and fire in semi-automatic mode, though the DMR and the Kel-Tec both use the 7.62x51mm NATO round, the Tavor however uses the 5.56x45mm NATO.
 * The DMR in multiplayer, takes four rounds to disable an enemy's energy shield, and a single headshot to kill. The range of the weapon is said to be further than the BR55 but because of reticule bloom, the user must fire at a controlled steady rate, or the weapon's spread ratio will be increased.