Stu goes over the Umarex H&K HK416 D GBB in this livestreamed presentation by Patrol Base... "Umarex's HK416 is truly a beast of a GBBR. The externals are to be marvelled at, with precise details well represented on the rifle and an absolutely flawless finish to all the parts. In line with other Umarex products, the external components consist of precisely machined aluminium parts, steel locking pins, springs, and trigger parts, and a steel outer barrel and muzzle device. The polymers used on this replica are practically identical to the real rifle, with a tough textured finish indicative of fibre reinforcement.

Starting at the tip of the barrel, we can find a steel birdcage flash hider that attaches to the 14mm CCW male threads at the end of the steel outer barrel with the help of a small grub screw. The steel construction of the outer barrel helps give the Umarex HK416 D a realistic centre of balance and weight distribution matching the real firearm. The barrel is finished appropriately in gunmetal grey, providing some contrast to the flat back of the rifle's rail system and receiver. Next, we arrive at the gas block, which is partially covered by the 9.5-inch quad rail system. The gas block provides mounting for a flip-up 416 type sight, and a dummy bayonet, and also features a sling loop on either side. The rail system itself provides 23cm of Picatinny rail at the 3, 6, and 9 o'clock positions, and a massive 36cm at the 12 o'clock position, thanks to the monolithic rail attachment interface. This gives plenty of room for whatever optical sight setup you fancy, along with space for PEQ laser units, tactical flashlights, and vertical grips, without things getting too cramped. The rail system features attractive vent holes along its length, reducing weight and grounding the modern HK416 D with classic H&K looks. The railed handguard can also be removed quickly and easily for cleaning, by removing a single locking screw on the right side of the rail, close to the receiver. From the factory the HK416 D comes with a pair of solid rotary drum dioptre sights, one of H&K's most beloved and timeless features, first appearing on the H&K G3A3. These sights are widely regarded as one of the best iron sight designs available, providing 4 apertures for different ranges whilst being adjustable for windage using the screw on the top of the rear sight. The front sight is a fine steel post, protected by large H&K style wings, ensuring an accidental bump doesn't upset your sights. These sights are removable and mount to the HK416's lengthy monolithic top rail.

The receiver of the HK416 D follows similar design principles to the M4/AR15 and has a familiar shape and configuration. The H&K linage of this GBBR is evident from a quick glance at the plethora of attractive H&K trademarks. The left side of the magazine well features laser engraved markings reading "HK 416 D Cal. 5.56mmx45", with an H&K logo above. The right side magazine well markings read "Licensed Trademark of Heckler and Koch GmbH Germany". There is also an H&K logo laser engraved into the bolt carrier and the left side of the upper receiver, completing the elite H&K look. The magazine release is on the right side of the receiver and lies well within reach of the trigger finger, making reloads quick and easy.

The bolt hold-open/release catch on the HK416 D is fully functional and will lock the bolt carrier to the rear at the end of a magazine. This can be found on the left side of the receiver of the rifle, positioned centrally, above the magazine catch. The bolt catch can also be used to manually lock the bolt open, by pressing on the lower section beneath the "ping pong paddle" as the charging handle is pulled. To release the bolt when it is locked, simply press the enlarged textured section of the bolt catch, also known as the "paddle", and the bolt will slam home.

The right side of the upper receiver features a mock brass deflector and the forward assist button. The steel forward assist button can be pressed, though it does nothing (same on the real rifle!). The fire selector can be found on either side of the receiver and provides high visibility pictograms to denote each firing mode. Though the receiver is marked with full-auto, this HK416 has been equipped from the factory as a DMR, and as such is locked to semi-automatic in both firing modes, and fires at a higher FPS than would be permitted for a fully automatic rifle. The pistol grip is right where you would expect it, and is an H&K enhanced grip. This provides a revised grip angle, aggressive checkering on either side and the rear of the grip, and a small, inoffensive finger grove. The combination of these features makes the pistol grip incredibly comfortable, filling the hand up nicely with the rounded profile. The grip also houses a storage compartment, suitable for housing spare batteries for optics, flashlights, and lasers, though you might be able to squeeze some tactical sweets in there too. The compartment can be accessed by turning the disk at the base of the grip counter clockwise by 90 degrees. At the rear of the receiver, we can find the charging handle, which is a classic AR15 low snag design. The catch to release the charging handle is on the left side and has a revised profile with additional texture to ensure you are able to maintain control of the handle at all times, even in wet weather or mud. The Umarex HK416 D is compatible with any magazine for the VFC GBBR system, including the Umarex HK416 GBB magazine and the VFC V-MAG.

At the very back of the receiver, we can find a familiar sight: the AR15 6 position buffer tube. This tube is GBBR spec, so cannot be replaced with alternative AEG spec tubes. The buffer tube is mounted via threads in the rear of the receiver and secured using a steel castle nut. The rear of the receiver is closed off with a steel buffer plate, which can be replaced with real AR15 spec sling plates, or Airsoft GBBR sling plates, should you see the need. The stock used on the Umarex HK416 D is an H&K Crane stock, featuring a low profile adjustment lever, textured rubber butt plate, and three sling mounting options. The low profile adjustment lever reduces the chances of your stock catching on slings or other equipment and is a welcome improvement to the traditional AR15 sliding stock design. The rubber butt plate provides incredible grip, ensuring your rifle stays in your shoulder when you need it to. The three sling points are found on the top of the stock, taking the form of 2 mirrored sling bars on either side, with a loop in the centre. This allows the HK416 D to be set up with a 2 or 3 point sling with very little effort and grants flexibility by allowing the sling to be mounted on either side. The buffer tube on the HK416 D is compatible with any aftermarket M4/AR15 stocks, allowing you to change up the rifle to fit you and your play style perfectly.

In order to adjust the HOP in the Umarex HK416 D, you will need to field strip the rifle, and remove its bolt carrier and charging handle. To do this, first, remove the magazine then rack the charging handle. Next, simply push the rear receiver pin through from the left side to the right, where it will remain captive in the receiver. Following this, the receiver will hinge apart around the front pin. The bolt carrier can then be removed, followed by the charging handle, which will need to be pulled rearwards then down, coming out through the same area through which the bolt carrier was removed. This will leave you with an empty upper, at the front of which you will note the silver chamber, at the bottom of which is the HOP adjustment grub screw. Using the provided Allen key, you can then adjust your HOP. To reassemble, place the charging handle back in first, with slightly less than half of the handle exposed through the rear of the receiver after that the bolt carrier goes in. Next, push the two parts fully back in as a unit, closing the receiver and pushing the locking pin back through once you have done so.

Internally, the Umarex HK416 D features a steel fire control group, prolonging the lifespan of the rifle and ensuring there are no weak spots in the mechanical components. The rifle also comes equipped with a 6.05mm tight bore inner barrel, providing exceptional accuracy. As a DMR platform, this HK416 will require some tuning and setting up to get the best out of it, though the fundamental components are already present; the rifle is pre-locked to semi-auto and shoots at DMR power levels from the box. This rifle would be perfect for an experienced Airsofter who wants to take DMR realism to the next level with immersive recoil and more realistic functions."