History
The United States Army's Delta Force, at the request of R&D NCO Larry Vickers, collaborated with the German arms maker Heckler & Koch to develop the new carbine in the early 1990s.[when?] During development, Heckler & Koch capitalized on experience gained developing the Bundeswehr'sHeckler & Koch G36 assault rifle, the U.S. Army's XM8 rifleproject (canceled in 2005) and the modernization of the British Armed ForcesSA80 small arms family.[citation needed] The project was originally called the HK M4, but this was changed in response to a trademark infringement suit filed by Colt Defense.
Design details
A
Norwegian soldier in
Afghanistan, armed with the HK416N.
The HK416 uses a HK-proprietary short-stroke gas system that derives from the HK G36, forgoing the direct impingement gas system standard in AR-15 rifles.[7] The HK G36 gas system was in turn partially derived from the
AR-18 assault rifle designed in 1963.
[8] The HK system uses a short-stroke piston driving an operating rod to force the bolt carrier to the rear. This design prevents combustion gases from entering the weapon's interior—a shortcoming with direct impingement systems.
[9] The reduction in heat and fouling of the bolt carrier group increases the reliability of the weapon and extends the interval between stoppages. It also reduces operator cleaning time and stress on critical components. According to H&K, "...experience that Heckler & Koch gained during its highly successful 'midlife improvement programme' for the
British Army SA80 assault rifle, have now borne fruit in the HK416."
[7]
The HK416 is equipped with a proprietary accessory rail forearm with
MIL-STD-1913 rails on all four sides. This lets most current accessories for M4/M16-type weapons fit the HK416. The HK416 rail forearm can be installed and removed without tools by using the bolt locking lug as the screwdriver. The rail forearm is "free-floating" and does not contact the barrel, improving accuracy.
The HK416 has an adjustable multi-position telescopic butt stock, offering six different lengths of pull. The shoulder pad can be either convex or concave and the stock features a storage space for maintenance accessories, spare
electrical batteries or other small kit items.
The trigger pull is 34
N (7.6
lbf). The empty weight of a HK416
box magazine is 250 g (8.8 oz).
The HK416's barrel is
cold hammer-forged with a 20,000-round service life and features a 6 grooves 178 mm (7 in) right hand
twist. The cold hammer-forging process provides a stronger barrel for greater safety in case of an obstructed bore or for extended firing sessions. Modifications for an over-the-beach (OTB) capability such as drainage holes in the bolt carrier and buffer system are available to let the HK416 fire safely after being submerged in water.
Differences from the M4
The HK416 is a variant of the American carbine, the
M4. It includes international symbols for safe, semi-automatic, and fully automatic. It has a redesigned retractable stock that lets the user rotate the butt plate, and a new pistol grip designed by H&K to more ergonomically fit the hand. A new single-piece hand guard attaches to the rifle with a free floating
RI system for mounting accessories.
The most notable internal difference is the short stroke gas piston system, which derive from the HK G36. To compensate for increased pressure due to the new gas system, it has a new, thicker barrel.
Furthermore, adjustable gas block with piston allows reliable operation on short-barrelled models, with or without a suppressor attached. Finally, the HK416 includes a folding front sight, and a rear sight similar to the
G3. The HK416 system is offered as an upper receiver, separate from the rest of the rifle, as a replacement to the standard issue
M4 upper receiver. It can attach to existing
AR-15 family rifles, giving them the new gas system, the new hand guard, and sights, while retaining the original lower receiver. The Heckler & Koch 416 can also be purchased as a fully assembled, stand alone carbine.