This .50 Caliber gun is great at mowing down masses. It's high impact rounds will penetrate armor completely.
("The old man wanted me to be a rice farmer. Found that lead farming was more my thing." - Private Ramirez")
One of the slower weapons, yet extremely powerful. The XM814 Heavy Machine Gun, or simply HMG, is able to bypass all enemy armor, dealing massive damage. It can be found as early as chapter one. However, it has its drawbacks. It has a painfully long reload, and is extremely heavy. Because of this there are few classes capable of putting the weapon to proper use, and many players are simply turned off by the weapon, refusing to use it.
Overall, the XM8 is one of the best weapons in NotD. It is strong in all areas except the aforementioned reload. For higher difficulties, its combination High Damage, High Splash, Armor Bypass, and High Ammo Conservation put it far above all other rifles and "primary weapons."
Efficiency by Character Class
1: Arms Assault
The HMG King. This class was built to use this weapon. Ammo Feed increases magazine size, making the long reload less frequent and more manageable. Critical Strikes and Blood Frenzy work in Nightmarish synergy to unleash massive damage. And Suppressive Fire increases the otherwise sluggish fire rate.
Critical Strikes and Fire Up upgrade to Focus Fire increases your damage output. Weapons Proficiency helps mitigate the poor reload speed and Grenades can be fired during the reload. Finally, Bloodlust helps to increase DPS while it is active.
Capable of turning even a dried stick into a lethal killing machine, the Op Comm is usually more at home using the UA420 Assault Rifle. However with an High-Capacity Magazines he can unleash hell with an HMG. The combination Adrenaline and Surgical Strike, with Weapons Expertise and Combo Reloads will make the XM8 near unstoppable for about 10 seconds.
Although It's Me Again and Synergize will work to heavily bolster the XM8's might, the Engineer has no way to mitigate the long reload times, unlike the other classes listed. The HMG also is not benefited by the armor reduction of Boom! Headshot, where another weapon such as the UA GPR-12 or MP9A2 Sub-Machine Gun would be. However it is still a solid choice if no other high damage class is available.