HK21 machine gun
E197571
The HK21 machine gun is a German-designed, belt-fed general-purpose machine gun developed by Heckler & Koch and based on the G3 rifle’s roller-delayed blowback system.
All labels observed (3)
| Label | Occurrences |
|---|---|
| HK21 machine gun canonical | 1 |
| Heckler & Koch 20-series machine guns | 1 |
| L7A2 GPMG | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T1677040 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: HK21 machine gun Context triple: [Heckler & Koch, product, HK21 machine gun]
-
A.
MG 131 machine gun
The MG 131 machine gun was a German 13 mm aircraft-mounted heavy machine gun used extensively by the Luftwaffe during World War II for defensive and offensive armament on various combat aircraft.
-
B.
MG 81 machine gun
The MG 81 machine gun was a fast-firing 7.92 mm German aircraft-mounted weapon used extensively by the Luftwaffe during World War II.
-
C.
7.62 mm M240 machine gun
The 7.62 mm M240 machine gun is a belt-fed, gas-operated general-purpose machine gun widely used by U.S. and NATO forces for infantry support and as a mounted weapon on vehicles and aircraft.
-
D.
Maxim machine gun
The Maxim machine gun is a pioneering late 19th-century recoil-operated, water-cooled heavy machine gun that became one of the first fully automatic weapons widely adopted by major armies around the world.
-
E.
M230 30 mm chain gun
The M230 30 mm chain gun is a single-barrel, electrically driven automatic cannon primarily used on attack helicopters for high-rate, accurate fire against ground targets.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: HK21 machine gun Target entity description: The HK21 machine gun is a German-designed, belt-fed general-purpose machine gun developed by Heckler & Koch and based on the G3 rifle’s roller-delayed blowback system.
-
A.
MG 131 machine gun
The MG 131 machine gun was a German 13 mm aircraft-mounted heavy machine gun used extensively by the Luftwaffe during World War II for defensive and offensive armament on various combat aircraft.
-
B.
MG 81 machine gun
The MG 81 machine gun was a fast-firing 7.92 mm German aircraft-mounted weapon used extensively by the Luftwaffe during World War II.
-
C.
7.62 mm M240 machine gun
The 7.62 mm M240 machine gun is a belt-fed, gas-operated general-purpose machine gun widely used by U.S. and NATO forces for infantry support and as a mounted weapon on vehicles and aircraft.
-
D.
Maxim machine gun
The Maxim machine gun is a pioneering late 19th-century recoil-operated, water-cooled heavy machine gun that became one of the first fully automatic weapons widely adopted by major armies around the world.
-
E.
M230 30 mm chain gun
The M230 30 mm chain gun is a single-barrel, electrically driven automatic cannon primarily used on attack helicopters for high-rate, accurate fire against ground targets.
- F. None of above. chosen
Statements (49)
| Predicate | Object |
|---|---|
| instanceOf |
belt-fed machine gun
ⓘ
firearm ⓘ general-purpose machine gun ⓘ |
| action | roller-delayed blowback ⓘ |
| barrelFeature | quick-change barrel ⓘ |
| basedOn | Heckler & Koch G3 rifle ⓘ |
| caliber | 7.62 mm ⓘ |
| canBeConvertedTo | magazine feed using G3 magazines ⓘ |
| cartridge |
.308 Winchester (commercial equivalent)
ⓘ
7.62×51mm NATO ⓘ |
| category | crew-served weapon ⓘ |
| chamberType | fluted chamber ⓘ |
| countryOfOrigin | Germany ⓘ |
| designer | Heckler & Koch ⓘ |
| feedSystem |
belt-fed
ⓘ
magazine-fed (with conversion) ⓘ |
| fireModes |
fully automatic
ⓘ
selective fire ⓘ |
| gasSystem | no gas system (recoil-operated, roller-delayed) ⓘ |
| hasVariant |
HK11
ⓘ
HK13 ⓘ HK21A1 ⓘ
linked to:
HK21
HK21E ⓘ
linked to:
HK21
HK23 ⓘ HK23E ⓘ |
| intendedUse | infantry support weapon ⓘ |
| introducedInDecade | 1960s ⓘ |
| isPartOf |
Heckler & Koch 20-series machine guns
ⓘ
linked to:
HK21 machine gun
|
| manufacturer | Heckler & Koch ⓘ |
| mountingOptions |
bipod
ⓘ
tripod ⓘ vehicle mount ⓘ |
| operatingPrinciple | roller-delayed blowback with fluted chamber ⓘ |
| primaryRole | general-purpose machine gun ⓘ |
| rateOfFire | approximately 800 rounds per minute ⓘ |
| relatedWeapon |
Heckler & Koch G3
ⓘ
linked to:
Heckler & Koch G3 rifle
Heckler & Koch MG5 ⓘ |
| safety | selector lever with safe and fire positions ⓘ |
| sightType |
iron sights
ⓘ
optical sight (with mounts) ⓘ |
| stockType |
fixed stock (standard)
ⓘ
optional retractable stock ⓘ |
| usedBy |
Brazilian armed forces
ⓘ
linked to:
Brazilian Armed Forces
German armed forces (limited and special units) ⓘ Greek armed forces ⓘ
linked to:
Armed Forces of Greece
Portuguese armed forces ⓘ
linked to:
Portuguese Armed Forces
various police and special forces units worldwide ⓘ |
| usedInConflict |
Cold War-era conflicts
ⓘ
Vietnam War (by some users) ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: HK21 machine gun Description of subject: The HK21 machine gun is a German-designed, belt-fed general-purpose machine gun developed by Heckler & Koch and based on the G3 rifle’s roller-delayed blowback system.
Referenced by (3)
Full triples — surface form annotated when it differs from this entity's canonical label.