The Patent behind the Heckler & Koch HK233 and HK237

Technically Heckler & Koch haven’t really released the HK233 yet. It’s “just there” on their homepage and they forgot to tell the marketing department to send out the press release.

But as we found out about the HK233 (5,56 NATO) and HK237 (300BLK) there were various people posting both in Facebook groups and at HKPro about the patent behind the rifle.

“Patent” isn’t a language I speak, especially combined with German. I learned that a long time ago, but there were some very interesting drawings that made more sense.

The patent from Heckler & Koch Gmbh was described as: “Adapter for mounting at least one additional device to a self-loading firearm, and equipped with this self-loading firearm”

and furthermore:

“The invention relates to an adapter (3) which is adapted for mounting at least one additional device (45) to a self-loading firearm (1), extends in weapons longitudinal direction, and having a tube side (25) and a housing-side (35) section. The adapter (3) is characterized in that it with one of its two portions (25; 35) on a holding device (79, 89) on the tube (19) or on the housing (4) can be fixed, and (with the other portion 25; 35) on the housing (4) or tube (19) by means of a longitudinally movable guide (96, 97, 109; 177, 179, 181) is movable storable. The invention also relates to a self-loading firearm (1) an adapter (3) according to one of claims 1 to 19, a holding device (79, 89) on the tube (19) or housing (4) for fixing the adapter (3), and a movable bearing on the housing (4) or tube (19) which is adapted to be longitudinally movable guide of the adapter (3).“

So this new patent is most likely HK’s solution to a problem that never officially existed ( Source), but it’s fixed now with the HK233. The HK233 is a G36 Version 2. At least it’s one way of looking at it, I’m sure there are other ways.

“If, for example, the tube emits heat to the housing during heat firing and expands or distorts it, which could occur, in particular, in the case of plastic housings, Or if the tube itself thermally warps, the additional device – largely because of the special adapter bearing – will be largely spared from tensions thus caused.”

You can find the sources of the Patent here:

https://encrypted.google.com/patents/DE102015013803A1?cl=en

and here:

https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=DE&NR=102015013803A1&KC=A1&FT=D&ND=3&date=20170427&DB&locale=en_EP#

The pictures and figures are from the sources mentioned above.

Look at the drawing above, N# 110. I think this design is interesting and worth discussing. If you look at the LWRC IC-A5 Individual Carbine the solution looks very similar, where you open or remove a lid to service the piston. There might be more rifles out there, with this solution?

If you add the knowledge, that a few Special Units have left / are leaving / are transferring from the H&K G36 to the LWRCI it becomes a bit ironic.

Here are two examples TFB recently reported about: https://www.thefirearmblog.com/blog/2017/04/21/lwrci-swedish-police/ and https://www.thefirearmblog.com/blog/2016/11/29/swedish-sog-special-police-units-get-lwrc-rifles/

The below picture is from the LWRCI IC Manual.

LIST OF REFERENCE NUMBERS
1 Self-loading firearm
3 adapter
4 casing
4a housing section
5 buttstock
7 grip
9 Fire selector lever / safety lever
11 deduction
13 trigger guard
15 magazine holder
17 Cocking lever
19 pipe
21 Bayonet recording / grenade launcher connection
23 Muzzle brake
25 Pipe-side section
27 Picatinny rail / top
29 Picatinny rail / bottom
31 breakthroughs
32 Keyhole
33 bridge section
34 passages
35 Housing-side portion of the adapter
36 Pin / bolt
37 recess
38 groove
39 Picatinny rail / rail
40 Recess for folding grain in Picatinny rail
41 Folding grain arrangement
42 Passages for bolt / pin for supporting the folding grain
43 Camp for folding rear sight assembly
44 Bilateral breakthroughs for storage of the folding rear sight
45 optical sight
46 Recess for folding rear sight in Picatinny rail
47 Pin / pins
48 folding rear sight
49 Holes in the adapter for hinge pin

End of Patent.

I have very little experience with the G36, but I do have experience shooting rifles fairly successfully. And I have a lot against the design which is now repeated in the HK233:

You have a barrel. On top of this barrel you mount a piston and a charging handle. On top of the piston you put more metal (or polymer), then you add some sort of carrying handle where you put your optic. On top of the optic you put another optic. Yes, I’m aware that all G36s don’t come with optics like pictured below, but even with a normal specification you have a sight line which is very high above the bore, and you are forced to compensate a poor design with cheek welds.

You don’t have to build a skyscraper to build a rifle.

The G36C shows what I mean. I’m sure it goes bang every time, but there’s room for improvements in other areas to make it easier to hit the target.