Words & pics: Rich Norman
Heckler & Koch’s headquarters at Oberndorf in Germany is known for its engineering design prowess and high quality manufacturing.
When Tier 1 USSOF need a pallet of 416Ds, it’s Oberndorf that manufactures them.
Oberndorf’s attention to detail is legendary, even down to the smallest part.
So when you see a metric torque setting, painstakingly inscribed on a high quality firearm component, chances are it’s a genuine Made in Germany Heckler & Koch product.
Part of the H&K ecosystem, the T-lugs on the reverse of this Picatinny rail segment occupy the male niche in the HKey microcosm.
The female niche is occupied by an absence: keyhole-shaped voids, in products such as the HK416A5 Slim Line hand guard.
HKey is H&K’s Magpul M-LOK equivalent, but it resembles VLTOR/Noveske’s KeyMod system (which is an M-LOK competitor).
It’s worth noting that both HKey and M-LOK are metric spec, whereas KeyMod is Imperial.
KeyMod is open source, whereas M-LOK isn’t; it’s free-licensed. It means that Magpul gets to say who can use it.
Until I found out about Magpul’s prerogative, I questioned why H&K hadn’t simply endorsed M-LOK – given the surge in that platform’s popularity in the US.
Now, however, my thinking is that H&K’s adoption of M-LOK would have been unlikely from the start. Some militaries adopt procurement doctrines which sensibly reject small arms which can be in any way restricted by a third party.
So, HKey avoids any unnecessary complications while also tying militaries further into the H&K ecosystem.
Should H&K have adopted KeyMod instead? There are probably many and varied reasons for not doing so, but KeyMod being non-metric won’t help its case in markets outside the US.
Despite being superficially similar, HKey and KeyMod are not interoperable.
Aside from a sling swivel (exhibited by the British Army L85A3 below, presumably during evaluation) HKey seems limited to Picatinny rail segments.
Rail segments are available in the following lengths: 54mm, 74mm and 95mm.
95mm segments are depicted here:
It’s not just the British Army that’s adopted HKey. H&K exports its rifles to militaries the world over and these Picatinny segments are starting to filter through in pics.
The examples I have in my possession are beautifully anodised in H&K’s interpretation of RAL8000.
Regular readers will know from my Fifty Shades of RAL8000 series that H&K seems to interpret RAL8000 as a family of low-observable colours, not one single tone. Whether the situation is by design or not, that’s the reality.
The stark differences that can occur in H&K’s RAL8000 colours is aptly displayed below, under two separate lighting conditions:
The Slim Line hand guard shown here is “RAL8000”, as are the HKey segments attached to it. The Assault Grip (reviewed here) is also RAL8000. None of the colours are true RAL8000, however, which is defined as a green-brown. Still, the HKey segments and the Assault Grip do match.
Each male T-lug at the rear of an HKey segment fits into the larger aperture of the female, keyhole-shaped void in the Slim Line hand guard.
The segment is then pushed forwards, so that each T-lug locks firmly into the narrow portion of the void. The rear section of the hand guard is scalloped in this area, so as to receive the disc-shaped head of the T-lug.
A T15 Torx wrench is required to secure the HKey segments to the hand guard.
As mentioned earlier, the torque setting of five Newtons per metre (5Nm) is inscribed on each segment.
Unlike KeyMod (which utilises uni-directional hooked lugs) HKey’s T-lugs are bi-directional. This means there is no upside down.
I owned a Noveske NSR rail several years ago and found no issues with KeyMod, aside from the availability of add-ons. HKey offers a similarly solid and robust mounting platform.
Read more about genuine H&K original parts here:
Heckler & Koch Quick Release Captive Rear BUIS
Heckler & Koch HK416 Slimline Stock
Heckler & Koch Receiver Extension
The Fifty Shades of RAL8000 series is here:
Fifty Shades of RAL8000 Part 1
Fifty Shades of RAL8000 Part 2
Fifty Shades of RAL8000 Part 3
Fifty Shades of RAL8000 Part 4
Fifty Shades of RAL8000 Part 5
The Reptile House 
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