HK433
Heckler & Koch · Assault Rifle · In Production · 2017
Also known as: G39
Overview
The HK433 is a select-fire assault rifle chambered in 5.56x45mm NATO, produced by Heckler & Koch GmbH since 2017.
Specifications
| Weight (empty) | 3500 g (123.5 oz) |
| Weight (loaded) | 3850 g (135.8 oz) |
| Overall Length | 989 mm (38.94") |
| Folded Length | 705 mm (27.76") |
| Barrel Length | 421 mm (16.57") |
| Action Type | Gas Operated |
| Trigger Type | Single Stage |
| Trigger Pull | 35 N (7.9 lbf) |
| Magazine Capacity | 30 rounds |
| Magazine Type | Detachable Box |
| Muzzle Velocity | 800 m/s (2625 fps) |
| Muzzle Energy | 1275 J (940 ft·lbf) |
| Effective Range | 400 m (437 yd) |
| Maximum Range | 3600 m (3937 yd) |
| Rate of Fire | 700 rpm |
| Barrel Rifling | Right Hand |
| Rifling Twist | 178 mm (7.01") |
| Number of Grooves | 6 |
| Frame Material | Polymer |
| Slide Material | Aluminum Alloy |
| Barrel Material | Steel |
| Stock Material | Polymer |
| Finish | Matte Black |
Calibers
- 5.56x45mm NATO · primary · 5.56x45mm NATO — also known as .223 Remington, 5.56 NATO, 5.56x45
Features
- Firing modes: Semi Automatic, Full Automatic
- Feed systems: Detachable Box Magazine
- Safety mechanisms: Ambidextrous Safety Selector, Firing Pin Safety
- Features: Ambidextrous Controls, Non Reciprocating Charging Handle, Accessory Rail, M Lok Handguard, Folding Stock, Adjustable Stock, Quick Change Barrel, Modular Design, Magazine Round Counter, Dual Control Modes
Variants
Service history
Operators
- German Special Operations Forces (KSK) · adopted 2020 · as G39
- Ukrainian Armed Forces · adopted 2024
- Jersey States Police · adopted 2025
- Schleswig-Holstein Police · adopted 2022
Conflicts
- Russo-Ukrainian War (2022-present)
Production
Production years: 2017-present
Limited production primarily for German special forces (988 HK437 rifles) and law enforcement contracts. Did not win the main Bundeswehr contract.
Origin
Country of origin: Germany
Designer: Heckler & Koch
Notes
The HK433 features interchangeable barrel lengths (280mm, 318mm, 368mm, 421mm, 480mm, 503mm) and can accommodate multiple calibers including 5.56x45mm NATO, .300 Blackout, and 7.62x51mm NATO through interchangeable lower receivers. The rifle offers two control configurations: push-button magazine release for AR-15-trained users or paddle-style for G36-trained users.
Background
The HK433 was developed as Heckler & Koch's ambitious attempt to create a truly modular rifle platform that could unify different operator preferences and replace the controversial G36. Despite being technically advanced and featuring innovative dual-control modes, it lost the German military's System Sturmgewehr competition in 2020 to the smaller German manufacturer C.G. Haenel, marking a rare competitive setback for the iconic firearms company.