The Heckler und Koch HK 437 “Sneaker” assault rifle (Germany)

The Heckler und Koch HK 437 “Sneaker” assault rifle was originally announced around 2017, along with a whole new family of the Heckler-Koch assault rifles chambered for the .300 Blk (7.62x35mm) ammunition. This new family included assault rifles such as the HK 237 (based on the 5.56mm HK G36 assault rifle), the HK 337 (based on the highly successful HK 416 assault rifle), and the HK 437, based on the then-new HK 433 assault rifle. Until 2022 there were no real news on the HK 437, but in late 2022 it was announced that the police force of the federal land Schleswig-Holstein (Germany) has ordered several hundreds of the HK 437 rifles, with intent to replace their ageing 9mm HK MP5 and MP5SD submachine guns. It is the first major contract for the new HK437 assault rifle.



The Heckler und Koch HK 437 assault rifle

The Heckler und Koch HK 437 assault rifle with a sound suppressor


It is worth noting that the HK 437 rifle is advertised by its maker as a dedicated weapon for use with a sound suppressor, and this why it is called the “Sneaker” by the HK. It is designed to fire the .300 Blackout (.300 BLK, 7.62x35mm) ammunition, which is rapidly gaining popularity for use in suppressed firearms for Special Forces. The cartridge, which is based on the .223 Rem parent case, for most practical purposes is very close to the old Soviet 7.62x39mm warhorse, but it is better optimized for the use in the platforms originally designed for the .223 / 5.56mm ammunition. The .300 Blackout is available both in the subsonic versions with heavy (~12 gram) bullets, and in the supersonic versions with relatively light 7-8 gram bullets, and is produced by several notable ammunition makers in USA and EU.

The HK437 in its design and functioning is the same gun as the 5.56mm HK433 assault rifle, except for the caliber and magazine well. It uses same short stroke piston, gas operated action and rotary bolt locking. Gun features manual gas regulator, which is especially useful when weapon is used with a sound suppressor. The barrels can be easily removed and replaced by an end user using simple tools. The upper receiver is made from an aluminum alloy, and the lower receiver is made from an impact resistant polymer. Non-reciprocating charging handle can be set up on either side of the gun, all other controls are ambidextrous. The HK 437 assault rifle is a select-fire weapon and can fire single shots and bursts of any length. HK also offers several types of sound suppressors (silencers) that can be quickly mounted onto the barrel of the rifle, made by B&T, Ase Utra and A-Tec. To avoid safety concerns with mixing up 5.56mm and .300Blk magazines, the HK437 assault rifle features a proprietary magwell and uses specially designed plastic magazines which would not fit into 5.56mm rifles.

The HK 437 assault rifle can be fitted with several versions of the shoulder stocks, which can be folded to the right, and also adjusted for the length. Sights (iron, Red Dot, telescope or Night/IR) can be easily mounted onto the integrated Picatinny rail that runs the entire length of the upper receiver.


The HK437 assault rifle, basic specifications

  • Caliber: .300 Blk (7.62x35mm)
  • Length: 795 mm; 537 mm with the stock folded, both with 229mm barrel
  • Barrel length: 178 or 229 mm
  • Weight: 3,14 kg less magazine and sound suppressor
  • Rate of fire: 850 rounds/minute
  • Magazine capacity: 10, 20 or 30 rounds