The HK21 is a light machine gun featured in Call of Duty: Black Ops.

Call of Duty: Black Ops


The HK21 is the secondary starting Weapon for Hudson on the level "Rebirth." It is very powerful and usually kills in one to two shots to the torso. It also has the ability to gib most enemies. It can also be found in other missions, such as "Numbers" and "WMD". Occasionally, it can be found with a Round Drum, which gives the player 80 rounds per drum. Though it is rare, it is a highly effective weapon if a Round Drum version is found.


The HK21 is a fully automatic light machine gun with moderate recoil, moderate rate of fire and a 30 round magazine. It is available at Level 2 to the player, as part of the LMG default class.

The HK21 will kill in 3 shots at any range, or 2 if headshots are involved, and has medium recoil. This makes the HK21 extremely powerful at medium range. Long-range encounters can be dealt with by firing small bursts. However, pairing the HK21 with Extended mags and Scavenger Pro allows for an extremely effective tactic: Extended fire at long ranges coupled with the easily controllable recoil and the high power of the HK21 will allow the user mow down enemies at chokepoints allowing for easy containment of the enemy when securing objectives. The HK21 is tied with the Stoner63 for the smallest capacity out of all the LMGs so the Extended Mags attachment is extremely useful, as it doubles the ammunition capacity to 60 rounds. The iron sights, while clear and open, can be difficult to use for some. For this reason, the Red Dot Sight or Reflex Sight is recommended.

Although the HK21 has very low movement speed, perks like Lightweight are not recommended. LMGs like the HK21 are better suited to large amounts of stationary fire, particularly when defending or supporting objectives. For this reason, Scavenger is recommended to keep supplied with ammo. Steady Aim benefits the HK21 as it improves its CQB capabilities. Sleight of Hand can also be very useful for this weapon, as it dramatically reduces the amount of time needed to reload, as well as improving ADS speed with the Pro version. Hardened or Warlord along with Extended Mags and a sight attachment can be more useful than Sleight of Hand.



The HK21 can be found in the Nazi Zombies game mode and is only obtained from the Mystery Box. It starts with a magazine size of 125 rounds and with an extra 500 rounds. When Pack-A-Punched, it becomes the 'H115 Oscillator', also giving it a Drum Mag (Extended Mags). This increases the magazine size to 150 rounds with 750 extra rounds plus the usual upgrades.

Due to this weapon's high power and large magazine, it is arguably one of the best non-Wonder Weapons in Zombies Mode.

The low rate of fire, very high magazine size and high reserve capacity makes ammo less of an issue for the HK21 than for other weapons. However, the very slow reload time makes Speed Cola useful when using this weapon. Double Tap Root Beer is also useful from rounds 18-20+ but the HK21 isn't as good as some may see it in Ascension because of the low fire rate and the removal of Double Tap Root Beer means the RPK, Galil and Commando are better options as they all have high ammo supply and higher rate of fire and in the case of the Galil and Commando: increased run speed. However this can be rectified for the HK21 by using Stamin-up. In Ascension, the HK21 can be viewed as a "love it or hate it" weapon. Some will love the high ammo, and others the good rate of fire and high movement speed.


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  • The HK21 has a noticeably slower rate of fire in Nazi Zombies
  • The HK21, MP5k, MP5 , and PSG-1 are based on the G3 rifle, and are all manufactured by Heckler & Koch, hence their similar appearance.
  • The HK21 in Nazi Zombies holds 125 rounds, even though it uses the 30 round magazine model. This was most likely for balancing reasons, as LMGs in World at War had more than a hundred rounds in Zombies.
  • The HK21 has a fingerprint on the back of the iron sight
  • When discarding the magazine, if one listens closely, it uses the same reload sound as the PPSH-41 from Call of Duty: World at War.
  • The "115" in 'H115 Oscillator' is a reference to Element 115.
  • Clan tags are placed on the rear of the iron sights and are completely clear and visible while aiming down the sights with no optical attachment.
  • On the Wii version, the handguard and stock are black, whereas the Xbox, PS3, and PC versions have a somewhat tan-olive color.
  • In third person the HK21 has a lot of muzzle flash, however, it is barely noticeable in first person.
  • While in first person, the right side of the trigger guard is missing.
  • The HK21 has the highest ammo-per-magazine of any weapon in Zombie mode.
  • In the Create-A-class display, the character's arm goes through a corner of the gun's stock.
  • The iron sights are always set to '2'.
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