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Although it saw more widespread use throughout all branches of the UNSC prior to 2548, it has since been superseded in use by the BR55 in all branches but the UNSC Army.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

Function and Usage
The M392 D.M.R.'s intended battlefield application is similar to that of the BR55 Battle Rifle, fulfilling a role as the most effective medium-to-long range weapon UNSC arsenal on Reach. It is intended for experienced marksman with proficient skill in "placing rounds" and "controlled firing" since multiple headshots must be attained in succession to effectively deliver maximum damage to the target and to ensure it is killed at the fastest possible rate. Due to the introduction of an expanding reticule, the DMR requires a considerably higher proficiency in controlled firing and precision than the BR55 to attain successive headshots at the optimum rate.

To deliver headshots to a target at long and medium-to-long ranges, pausing after each shot with the DMR is required to allow the reticule to contract to its smallest possible size, then immediately firing again to maintain maximum rate of fire. While at close-to-medium range, it is only necessary to allow the reticule to shrink enough that it is roughly equal to the size of the target's head/helmet before firing again. At extremely close ranges, it is unnecessary to allow the reticule to contract at all, and it is most effective to fire the rifle as fast as possible, whilst still aiming for the head.

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 weapon as a "Designated Marksman Rifle" indicate that it was designed for use in squad-based combat, and not as a dedicated sniping tool. In the U.S. military, designated marksmen function provide long-range support to their platoon. This contrasts with snipers, who operate in small teams and receive more specialized marksmanship training.
 * This weapon's semi-automatic functionality is similar to the Battle Rifle in the 2003 Halo 2 E3 Demo.
 * The DMR was first featured in "The Art of Halo 3" as a concept design for the Halo 3 Battle Rifle.
 * In the Halo: Reach Multiplayer Beta, the DMR ejects the casing of the 9.5x40mm round used by the BR55 series, instead of the 7.62x51mm round which it actually fires.
 * The number of the model (M392) may be a reference to 7 (3+9+2=14 and 14/2=7).