Heckler & Koch HK91
Heckler & Koch · Battle Rifle · Out Of Production · 1974
Also known as: HK 91, HK G3 civilian, Heckler & Koch Model 91
Overview
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.
Specifications
| Weight (empty) | 4400 g (155.2 oz) |
| Overall Length | 1025 mm (40.35") |
| Folded Length | 840 mm (33.07") |
| Barrel Length | 457 mm (17.99") |
| Action Type | Roller Delayed Blowback |
| Firing Mechanism | Hammer Fired |
| Trigger Type | Single Stage |
| Magazine Capacity | 20 rounds |
| Magazine Type | Detachable Box |
| Muzzle Velocity | 800 m/s (2625 fps) |
| Muzzle Energy | 3300 J (2434 ft·lbf) |
| Effective Range | 600 m (656 yd) |
| Maximum Range | 1000 m (1094 yd) |
| Barrel Rifling | Right Hand |
| Rifling Twist | 305 mm (12.01") |
| Number of Grooves | 4 |
| Frame Material | Steel |
| Barrel Material | Steel |
| Stock Material | Polymer |
| Finish | Phosphate |
Calibers
- 7.62x51mm NATO · primary · 7.62 NATO — also known as .308 Winchester
Features
- Firing modes: Semi Automatic
- Feed systems: Detachable Box Magazine 5 10 20, Drum 30 40 50
- Safety mechanisms: Manual Safety Three Position, Welded Receiver Shelf Anti Full Auto
- Features: Roller Delayed Blowback, Stamped Steel Receiver, Fluted Chamber, Rotary Diopter Drum Rear Sight, Hooded Front Post, Polymer Furniture, Drum Magazine Compatible
Variants
- HK91A2 — Fixed Stock
- HK91A3 — Retractable Stock
- HK91A4 — Polygonal Bore
- HK91A5 — Polygonal Retractable
- HK SR9 — Post Ban Thumbhole
- PTR-91 — Us Clone
Base model
Service history
Operators
- Civilian US sport/collector market · adopted 1974 · as HK91
- Limited US law enforcement · as HK91
Production
Estimated total produced: 48,817 · Production years: 1974-1989 (US imports)
48,817 confirmed pre-ban US imports. Predecessor HK41 (1964-1976) only ~400 units. Production continued internationally; US-specific imports halted by 1989 Bush import ban.
Origin
Country of origin: Germany
Discontinued: 1989
Notes
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).
Background
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.