Origin: West Germany
Year: 1968
Type: Assault rifle
Caliber: 5.56x45mm NATO
Weight: 3.65 kg (8.05 lb)
Length: 920 mm (36.2 in)
Barrel length: 390 mm (15.4 in)
Capacity: 30 rds (25 and 40 rd magazines available)

The HK33 is a 5.56mm NATO entry into the iconic Heckler & Koch family of firearms based on the G3 design. Though not adopted by the German military for general issue (where the G3 in West German and AK-pattern rifle in East Germany served until replaced by the H&K G36 series after unification), the HK33 did see quite a bit of success as an export rifle as well being manufactured under license in other nations. The rifle is a select-fire design utilizing the same roller-delayed blowback system as used by the 7.62x51mm G3 and HK91, the 7.62x39mm HK32, and 9x19mm MP5 and HK94. Notable military users of the HK33 and its short-barrelled HK53 variant include Ecuador, Chile, Thailand (where it is also manufactured under license), the United Kingdom (used the Special Air Service), the United States (limited experimental use by US special forces with the Harrington & Richardson-built clone T223), Indonesia (in service with special forces units), and Turkey. It has also seen service with law enforcement agencies such as the Royal Ulster Constabulary (RUC) and its successor the Police Service of Northern Ireland (PSNI), US Border Patrol, and the Spanish National Police Corps. Semi-automatic versions of the rifle are also popular on the US civilian market with both American and foreign made clones available.