The HK21 is a general purpose machine gun made by German firearms company, Heckler & Koch in 1961. It, like many of H&K's weapons, is based on the successful G3 assault rifle. The weapon is in use with the armed forces of several Asian, African and Latin American countries. It was also license-manufactured by Fábrica de Braço de Prata in Portugal as the m/968 and in Mexico by SEDENA as the MG21. In the German military (Bundeswehr) and the federal police (Bundespolizei) it is designated G8
It is chambered in the 7.62x51mm NATO round is fed from a variety of disintegrating belt ammunition. It can be modified to accept the G3's 20-round box magazine, or a 50-round drum magazine designed for the weapon.
— In-game description
The HK21 is a weapon featured in the Battlefield 2: Euro Force expansion as the standard light machine gun of the European Union Support kit. The HK21 features a 200-round belt in a box, as well as a moderate firerate and medium-high damage. It is fairly accurate when crouched or prone, but when standing, it has significant spread. The HK21's reload time is high, along the same average for the light machineguns.
- The in-game description erroneously states that the HK21 has an 800 round-per-minute firerate when in fact it has only a 600 round-per-minute firerate.