The Heckler & Koch HK433 at EnforceTac 2017

Just over a month after the breaking news that H&K are releasing the HK433 in 5,56×45 mm we now have more information (and facts rather than rumors and some funny translations).

We have also seen the “Four-Three-Three” live. Behind glass and in front of a large crowd, but still. As much as we would have loved to pick one up to feel and examine this was unfortunately not possible at EnforeTac 2017 in Germany.

The HK433 is very compact and seems to have nice ergonomics. It looks light, but without a scale it’s hard to know if it’s lighter than the current M4 versions. The backbone of the rifle is tested in various platforms, but the total package is new so it will be interesting to see what end-users will find out and discover in the field.

According to HK, the 433 is supposed to be more reliable than the HK416.

Will taking the best of the G36 and the HK416 into one rifle work and who will be the first one to find out the good and the ugly?

The HK433 was displayed with a Zeiss ZO 4×30.

Notice that the upper and handguard have changed slightly and that the lower is quite different. This EnforceTac rifle also had a G36 paddle style magazine release.

Below follows a deeper explanation of the functional elements and operating concept of the HK433, with live pictures from Germany and the catalogue.

The Functional Elements of the HK433.

FLASH HIDER – Tool-free mounting of suppressors and blank firing attachments.

MUZZLE THREAD M15x1 muzzle thread for mounting a blank firing attachment.

GAS PORT The gas port is adjustable without tools.

DISASSEMBLY Tool-free assembly/disassembly of the major assemblies with captive pins, simple cleaning.

CHARGING HANDLE Flat charging handle with integrated forward assist function. Charging handle convertible from left to right without tools.

SIGHT RAIL Monolithic sight rail (STANAG 4694) with low line of sight.

OPERATING CONCEPT Symmetrical and ambidextrous operating concept.

SAFETY LEVER WITH 45° TRAVEL Ambidextrous operation without
changing the grip position. Cocking in all safety positions possible.

CHEEK REST Height-adjustable cheek rest.

BUTTSTOCK The foldable and retractable buttstock can be locked in 5 positions over an adjustment travel of 84 mm

BUTTSTOCK INTERFACE Foldable buttstock interface without play.

SHOULDER PADS Available with straight, convex or concave shoulder pads.

PISTOL GRIP Modular AR-15 pistol grip interface. Optional: Ergonomic grip shape with exchangeable back straps and grip shells.

LOWER RECEIVER Exchangeable lower receiver.  Ambidextrous operating concept for G36 or HK416/AR-15 users.

MAGAZINE/MAGAZINE WELL NATO magazine compatibility as per STANAG DRAFT 4179

A detailed look below:

Left: G36 magazine release lever.                                     Right: HK416 / AR-15 magazine release lever

ROUND COUNTER Maintenance-free round counter integrated in receiver. Stores information on serial
number, weapon type, year of manufacture, manufacturer identification, etc. Data is being read using RFID technology.

HANDGUARD Handguard with HKey interfaces at 3 and 9 o’clock positions and Picatinny rail as per  MIL-STANDARD 1913 at 6 o’clock position (optional STANAG 4694) – for mounting tactical

INTERFACE Interfaces for grenade launchers, e.g. GLM/GLM A1 or HK269.

BARREL Barrel length/barrel version individually configurable. Interfaces available such as front
sight adapters, bayonet adapters or adapters for rifle grenades.

The Operating concept of the HK433 (note numbers to the text below for clarification)

The replaceable lower receiver defines the desired operating concept, thus reducing the training expenses for the shooter. Depending on the shooting training, the shooter can choose between a G36 and an HK416/AR-15 operating concept. All operating elements are attached on both sides, arranged  symmetrically and can be customized. “Drop-in“ solutions of the lower receiver extend the range of functions of the weapon with respect to match triggers or trigger assembly combinations.



2 Handguard

The Slim Line handguard is positivie-locking and connected to the upper receiver free of backlash. It can be removed without a tool and offers carrying sling fixing points, modular HKey interfaces on 3 and 9 o‘clock as well as a continuous MIL-STD-1913 Picatinny rail on 6 o‘clock.

3 Round counter (optional and seems similar to FN Herstal’s solution)

The upper receiver has a built-in maintenance free round counter. The weapons data can be transmitted and archived wireless. The round counter requires no energy supply. Data is read using RFID technology.

4 Buttstock
The ergonomically foldable and length adjustable buttstock with height-adjustable cheek rest is free
of backlash and connected to the receiver. The length adjustment has five locking positions, allowing it to be adjusted dynamically to the personal protective equipment of the shooter. Moreover, the buttstock can be folded to the right in each locking position. Even though, the trigger always remains freely accessible. The case ejection port is not covered, ensuring the ability to defend in an emergency in the transport mode.

5 HK pistol grip ergonomics
The grip interface is designed similar to the HK416 weapons family. Pistol grips with exchangeable grip
shells and back straps similar to the P30 and SFP/VP series of pistols are optional possible.

6 Magazine compatibility
The magazine well according to NATO STANAG 4179 (draft) ensures interoperability of the G36 weapon systems with HK conversion magazine well, the HK416, and the commercially available AR-15 platforms.

7 Barrels
The HK433 gives the shooter six different barrel length options, allowing him to adjust the weapon to the particular operational need. As standard, the barrels are equipped with a further-developed and toolless adjustable gas port for sound suppressor operation and an interface for the 40 mm grenade launcher
HK269 and the GLM/GLMA1. A front sight interface and bayonet holder can be mounted on the barrels as an option. All barrels can be replaced at the operators and maintenance level.

Below: The “wrong” end of the HK433. Note the protruding charging handle, this can be changed to the right side also.

My understanding is that the charging handle works as a forward assist. The World’s first ambidextrous?

Well, this has got to be the right side of the rifle from a shooter’s perspective. So close, yet so far away.

Optics: Zeiss ZO 4×30

The receiver is extruded aluminum and monolithic.

We have listed the features before, but this is from the actual catalogue instead of a translation.

HK433 Features

  • Modular and light design. Compact dimensions.
  • Barrel length individually configurable. Easy barrel exchange at the operators or maintenance level.
  • Fully ambidextrous weapon operation for both right-handed and left-handed shooters.
  • Non-reciprocating charging handle, convertible from left to right without tools.
  • Special material properties and surface treatments allow for a reliable and low-maintenance system suitable for the most extreme conditions.
  • Lower receiver with double-sided operating concept for G36 or HK416/AR-15 users.
  • Drop safety as per AC225/D14 when on or off safety.
  • Monolithic upper receiver with STANAG 4694 profile at 12 o’clock position. Modular Slim Line handguard with HKey interfaces on 3 and 9 o’clock positions as well as Picatinny rail as per MIL-STD 1913 on 6 o’clock position.
  • Maintenance-free round counter integrated in receiver, no energy supply required.
  • Foldable, retractable buttstock with height-adjustable cheek rest. Weapon can also be used with the buttstock in the folded-in position.
  • Bolt with an emergency operation feature due to self-lubricating sliding elements
  • Tool-free assembly/disassembly of the main assemblies.
  • Cocking in all safety positions possible.
  • Wide variety of accessories available, such as training bolt group, bayonet, suppressor, drum magazine, brass catcher, blank firing attachment, forward grip or bipod.
  • Infrared-absorbing coatings possible.

According to HK we’re to expect a version in .300 Blackout as well, which is no surprise.