Heckler & Koch HK91
- Category
- Battle Rifle
- Barrel
- 457 mm
- Weight, empty
- 4.40 kg
- Introduced
- 1974
About
What it is, and why it matters
The HK91 is the civilian semi-automatic export version of the Heckler & Koch G3 battle rifle, chambered in 7.62×51mm NATO. Imported into the United States from 1974 to 1989, when the Bush administration's import ban on semi-auto rifles ended further importation. The platform uses the proven roller-delayed blowback action with stamped-steel receiver and polymer furniture, and includes a welded-in receiver shelf that mechanically prevents installation of an automatic-fire trigger group. Known for rugged construction, fluted chamber, drum-style diopter sights, and the signature 'HK slap' charging procedure, pre-ban examples are highly sought-after collector pieces today, fetching $2,000–$5,000+ depending on condition and variant.
The 1989 Bush administration import ban on semi-auto 'assault rifles' froze HK91 supply overnight, sending pre-ban examples to premium collector pricing. The platform proliferated post-ban via PTR Industries (founded 1997) using H&K-licensed tooling acquired from Fábrica de Braço de Prata in Portugal. The signature 'HK slap' - slamming the cocking handle down from its forward notch to chamber a round - entered tactical/firearms culture through this platform.
Successor designation HK911 used by some late US importers. After 1989 import ban, HK introduced the SR9/SR9T/SR9TC with thumbhole stocks, fixed mags, and no flash hider/bayonet lug to comply with sporting-purpose test. Platform proliferates today via PTR-91 (PTR Industries) using H&K-licensed tooling acquired from Fábrica de Braço de Prata in Portugal. Total US import: 48,817 units (~130 additional in customs at ban time).
Specification
Everything measured
IdentityWhat it is, who built it and when.
- Manufacturer
- Heckler & Koch
- Category
- Battle Rifle
- Country
- Germany
- Status
- Out of production
- Produced
- 1974 to 1989
- Variant of
- Civilian export
DimensionsAs issued, without a magazine or an optic.
- Barrel
- 457 mm
- Overall length
- 1025 mm
- Weight, empty
- 4.40 kg
ActionHow it cycles, what trips it, and what feeds it.
- Action
- Roller delayed blowback
- Firing mechanism
- Hammer fired
- Trigger
- Single stage
- Capacity
- 20
- Magazine
- Detachable box
MaterialsEach swatch is the material itself, not a colour chosen to stand for it.
- Frame
- Steel
- Barrel
- Steel
- Stock
- Polymer
- Finish
- Phosphate
BallisticsFrom the service cartridge, not a handload.
- Muzzle velocity
- 800 m/s
- Muzzle energy
- 3300 J
- Effective range
- 600 m
- Maximum range
- 1000 m
Trajectory
What the round does downrange
Solved from the muzzle figures and the bullet. The dashed rule is the effective range on the record, and the crosses are the steps the solver returned.
Features
What it has
What the record lists as fitted, drawn from the catalogue.
Roller delayed blowback
Stamped steel receiver
Fluted chamber
Rotary diopter drum rear sight- Hooded front post
Polymer furniture
Drum magazine compatible
Standing
How it compares
Each figure against the firearms of the same type and cartridge that record it, or of the same type where that cartridge has too few. Positions are read to the nearest tenth.
| Measurement | This firearm | Median | Position |
|---|---|---|---|
| Empty weightAmong 86 7.62x51mm NATO battle rifles | 4.40 kg | 4.30 kg | Heavier than about 70% |
| Overall lengthAmong 85 7.62x51mm NATO battle rifles | 1025 mm | 1025 mm | Near the median |
| Barrel lengthAmong 87 7.62x51mm NATO battle rifles | 457 mm | 458 mm | Shorter than about 60% |
| Magazine capacityAmong 87 7.62x51mm NATO battle rifles | 20 | 20 | Near the median |
Answers
Questions about the Heckler & Koch HK91
How much does the Heckler & Koch HK91 weigh?
The Heckler & Koch HK91 weighs 4.40 kg (9.70 lb) empty.
What caliber is the Heckler & Koch HK91?
The Heckler & Koch HK91 is chambered in 7.62x51mm NATO.
How many rounds does the Heckler & Koch HK91 hold?
The Heckler & Koch HK91 holds 20 rounds, fed from a detachable box magazine.
How long is the Heckler & Koch HK91?
The Heckler & Koch HK91 is 1025 mm (40.4 in) long overall, with a 457 mm (18.0 in) barrel.
Who makes the Heckler & Koch HK91?
The Heckler & Koch HK91 is made by Heckler & Koch (Germany).
When was the Heckler & Koch HK91 introduced?
The Heckler & Koch HK91 was introduced in 1974 and discontinued in 1989.
How does the Heckler & Koch HK91 operate?
The Heckler & Koch HK91 uses a roller delayed blowback action, and its firing mechanism is hammer fired.
Compatibility
Which parts fit this firearm
Studio
Every part that mounts on this, resolved
Not a list the maker typed out: the answer comes from the mounts this firearm exposes and the interface each part needs, so it stays right when either one changes.
- Every part that mounts on any firearm in the catalogue
- Interface standards, platforms and fit overrides
- The same answers through the API and the MCP server
Requires a signed-in GunSpec account on the Studio plan. The answer is computed per part, so it is not part of the public record.
Provenance
What the record holds
Every figure above was taken from one of these pages. The confidence reflects how much of the record came from a page a claim can be checked against.
In service
- Civilian US sport/collector market
- 1974
- Limited US law enforcement
- United States
Provenance
Confidence in this record
90%
Stockists
Where to buy
Offers link straight to the shop. GunSpec never takes the order.
No shop has listed this firearm yet
Stock and prices come from the shops themselves. If you sell this firearm, you can list it and it appears here.
List a firearmMCP
Ask an assistant about it
The same record, reached the way a person asks for it rather than the way a program does.
Ask GunSpec
Works with
Point an MCP client at GunSpec and it answers from the catalogue rather than from memory. A free key covers the read tools.
API
The call that returns this record
The same fields, in the same units, from the same endpoint the page reads.
curl --request GET \ --url 'https://api.gunspec.io/v1/firearms/hk91' \ --header 'X-API-Key: your_key'{ "id": "hk91", "name": "Heckler & Koch HK91", "manufacturer": { "id": "heckler-koch", "name": "Heckler & Koch", "countryCode": "DE", "foundedYear": 1949, "website": "https://www.heckler-koch.com", "logoUrl": null, "description": null, "status": null, "defunctYear": null, "stateOwned": null, "makesFirearms": null, "parentId": null, "predecessorId": null, "createdAt": "2026-04-05 22:24:37", "updatedAt": "2026-04-05 22:24:37", "version": "ae60994f5b45d604da21fcd14b728cfa9d2e62000c92e596de4c48c4be768979" }, "category": { "id": "battle-rifle", "name": "Battle Rifle", "description": "Selective-fire rifles chambered in full-power cartridges" }, "country_of_origin": "DE", "year_introduced": 1974, "barrel_length_mm": 457, "weight_empty_g": 4400, "action_type": "roller_delayed_blowback"}