Heckler & Koch MR223

The MR223 is the civilian counterpart for the HK416 – the latter being the weapon which made many of those working in the industry claim that “M16 has finally reached a state-of-the-art level” .

In order to eliminate the main shortcomings of the M16 – i.e.  the tendency of the weapon to get clogged with carbon residue – Heckler & Koch has replaced the direct gas inpingement system with an indirect system via short-stroke piston, which is exactly the same of the G-36 and the XM8.

Heckler & Koch MR223
The gas block on the barrel houses the folding front sight and the front carry strap attachment. The bayonet lug of the military version has been removed in the MR223

We had a chance to try a few  different configurations of the MR223, all of them featuring a collapsible stock, FFRS handguard (Free Floating Rail System) and 16,5” barrel chambered in the civilian .223 Remington caliber instead of the military 5.56mm NATO.

The MR223 appears to be a high-quality product. Material manufacturing and finish is excellent. The standard gun configuration  comes with a compensator/flash hider permanently attached to the muzzle and, as we mentioned above, a special aluminum alloy handguard equipped with Picatinny rails for additional accessories installation.

The handguard keeps the barrel fully floating, and is accurately installed on  a prolonged “barrel nut” , so as to maintain the handguard perfectly coaxial with the barrel under any condition.

Heckler & Koch MR223
The rear drum diopter sight is pure HK in design and is identical to the one used in every roller locked weapon systems marketed by H&K before the G36, such as the MP5 and the G3. The whole upper receiver features a full length Picatinny rail

The handguard is aligned through its simple joint with the upper receiver, in such a way as to offer a continuous  single upper rail between the upper receiver and the handguard.

The handguard has been installed on the barrel nut with a screw, which can be removed using one of the bolt locking lugs or the proprietary snap-hook of the carry strap.

The folding front sight is installed on the barrel gas group, therefore being on the barrel and not on rail – this means a greater shooting precision when using metal sights.

The rear diopter sight, installed on the weapon with a Picatinny interface,  is virtually identical to the one used on “classic” roller-locked HK weapons such as the MP5 and the G3. This does not mean that it is not possible to employ an alternative iron sights BUIS standard for AR15, in addition, obviously, to the main optics package.

Concerning ergonomics, MR223 differs from the typical “Black Rifle” because of the size and the shape of the collapsing stock and the different angle of the pistol grip, which is much straighter. 

Heckler & Koch MR223
The MR223ʼs nice collapsible stock can easily be adjusted to different lenghts; it can be removed, and if really the owner does not like it, it can be replaced with an aftermarket, i.e. a Magpul

Concerning ergonomics, MR223 differs from the typical “Black Rifle” because of the size and the shape of the collapsing stock and the different angle of the pistol grip, which is much straighter.

The controls of the weapon are positioned in the same way as those of any other AR15. Unlike the 416 model, the MR223 does not have the ambidextrous safety catch selector.

The 5-round capacity magazine is a standard STANAG model. 

The MR223 is a classic gas operated, short-stroke piston system. In fact, the pattern is very similar to the one used by the HK G36. Once the round is shot, the bullet runs along the barrel until, about half-way through, passes the gas port in the bore.

Heckler & Koch MR223
A configuration of the Heckler & Koch MR223, with Eotech optics, weaponlight and aiming laser manufactured by Laser Devices
Heckler & Koch MR223
Left side of the MR223, with the controls in the usual places typical of the AR15 platform. Note that the safety lever is actually an assembly; the serial number is marked on both upper and lower receivers

The gases coming out of the barrel go into the gas block and are later channeled to a cylinder, where the head of the piston rests. The latter, in turn, is connected to an arming rod – which does not reciprocate with the bolt carrier group – and is equipped with its own return spring. Gases in excess are disposed of through a valve equipped with a tuned hole. 

The arming rod, which moves under the effect of the pressure applied by the gas on the piston, moves just a  few millimeters back – from here comes the term “short-stroke piston” – giving a kinetic impulse to the bolt carrier group, which starts its backward travel.

The movement of the bolt carrier group, thanks to a cam milled through the body of the bolt carrier, forces the bolt to rotate on its axis, releasing it from the locking lugs in the barrel extension.

Heckler & Koch MR223
The Forward Assist is still present. The take down pin has been relocated forward by 6 mm vs. the military version 416 (and any other AR15); there is no ambidextrous safetylever

The bolt carrier group, once all kinetic energy has been spent and the hammer has been armed again, returns to its previous position, stripping a new round off the magazine, chambering it and locking again, thus preparing the weapon to fire again. 

The 16.5” barrel (461 mm length) is made of cold-hammered forged steel, with a right-handed rifling, featuring 6 right-handed grooves, with a 1:7 pitch. The manufacturing process requires special high-quality types of steel and chrome plating for the bore of the barrel itself, in such a way as to obtain a barrel which is capable of attaining high rates of accuracy even after over 20 thousand rounds have been fired.

The bolt carrier group is not equipped with a gas key, that is the small pipe through which the gas coming out of the barrel is channeled – as the direct gas impingement system requires – rather a monolithic prism on which the arming rod imparts the kinetic impulse. The chrome-plated bolt is equipped with 7 radial locking lugs and is much tougher of the one on the AR15. 

Heckler & Koch MR223
Right side view of the Heckler & Koch MR223
Heckler & Koch MR223
Left side view of the Heckler & Koch MR223
Heckler & Koch MR223
The HK MR223 field strippin is very similar to any other AR15
Heckler & Koch MR223
The MR223 ejection window. Note that the exhaust gas ports have disappeared from the bolt carrier; the door is plastic!

It is worth mentioning the presence of a contrast spring on the firing pin, so as to avoid to mark the primer and a possible slam fire – which is a typical problem of the AR15 –and of an automatic safety catch for the firing pin, which is disabled by the hammer when in firing position.

The main recovery spring,  in the buffer tube, is 20 percent stronger than the original one and uses a newly designed buffer. The tail of the bolt carrier group has also been partly re-designed, as it now features a large sliding surface.

The bolt carrier group has a milling on left side which corresponds with a block on the barrel extension – the latter serving the purpose of preventing the use of military bolt carrier groups on the MR223. 

The collapsible stock features some watertight compartments which can be used for storing batteries and some small spare parts. 

Heckler & Koch MR223
The Heckler & Koch MR223 with Zeiss Z-Point optics during live fire testing

When shooting, felt recoil is extremely light. The weapon appears to be just a bit more “nervous” than a standard AR15, while muzzle climb is virtually non-existent, so is the flash in the muzzle.

The firearm’s handling is actually good, although most of the weight is concentrated in the front, making the gun “muzzle-heavy”, but when taking aim at the target the firearm reacts in quite a natural way. The MR223 is extremely stable when shooting from a stand-up position, thus allowing for very fast follow-up shots . 

Our final opinion on the gun is positive, but,  considering its relatively high price,  there is some margin for improvement – i.e. the trigger. Other features, such as the plastic ejection port door, directly come from the military version of this weapon.

 All in all, the overall quality of the weapon is very high. The weapon comes equipped with a set of excellent metal BUIS sights, a RAS handguard – which provides the same stability a monolithic upper can provide – a high quality collapsible stock and an overall excellent performance with an HK brand on the Lower. Not bad at all.