HK21

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

Campaign
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 &quot;Numbers." Sometimes it can be found with the round drum, which gives it 80 bullets per magazine, making it a very effective weapon if such a thing is found.

Multiplayer
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 1 to the player, as part of the LMG default class.

The HK21 will kill in 3 shots at any range, or 2 headshots, and has medium recoil. This makes the HK21 extremely powerful at medium range. Long-range encounters can be dealt with by firing small bursts. 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.

Attachments

 * Infrared Scope
 * Red Dot Sight
 * Extended Mag (Drum Mag)
 * ACOG Scope
 * Reflex Sight thumb|300px|right|HK21 Attachment Overview

Zombies
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 while increasing ammo capacity along with the usual additions.The H115 Oscillator only makes the power of the gun better than the HK21.

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. The low rate of fire also makes Double Tap Root Beer beneficial, but not a necessity. Be aware that Double Tap Root Beer increases the upwards recoil a significant amount. It may be wise to switch to a weapon with more mobility if fleeing becomes necessary, as the HK21 slows movement speed significantly.

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

Trivia

 * In Nazi Zombies, the HK21 has a noticeably slower rate of fire.
 * This weapon is very similar in appearance to the G3 and the PSG1 because they are both based off the G3 rifle - the PSG1 is a sniper rifle variant and the HK21 is an LMG variant,.
 * The HK21 in Nazi Zombies holds 125 rounds even though it uses the 30 round magazine model. The weapon would have to be used in the belt-fed configuration in order to hold this much ammunition. This was most likely for balancing reasons.
 * It has a finger print on the back of the iron sight
 * When discarding the magazine, if one listens closely, it has the same reloading 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.
 * In the Wii version the handguard and stock are black, where the XBOX, PS3, and PC versions have a somewhat tan-olive color.
 * The bipod is always down.