The Heckler & Koch HK417 is a battle rifle/designated marksman rifle designed and manufactured by Heckler & Koch in Germany. It is the larger caliber version of the HK416, and chambered for the 7.62×51mm NATO rifle cartridge. It is a gas-operated, selective fire rifle with a rotating bolt. The HK417 is intended for use in roles where the penetrative power, stopping power, and range of the 7.62×51mm cartridge are required. It has been adopted for service by a number of armed forces, special forces, and police organizations.
Design and features
The HK417 is similar in internal design to the HK416, although the receiver and working parts are enlarged to suit the larger 7.62×51mm cartridge. The bolt is a seven-lug rotating type, which sits in a bolt carrier and operates in a forged alloy receiver resembling those of the Stoner-designed AR-10, AR-15 and M16 rifles.
Like the HK416, the HK417 is gas-operated with a short-stroke piston design similar to that of the Heckler & Koch G36. The short-stroke piston may be more reliable than the original direct impingement operation of the AR-15 design because, unlike these weapons, it does not vent propellant gases directly into the receiver, which deposits carbon fouling onto the bolt mechanism as well as heating it up.
The early HK417 prototype used 20-round magazines from the Heckler & Koch G3 rifle family, which did not feature a bolt hold-open device. Later prototypes, however, switched to a polymer magazine with bolt hold-open. The magazine resembles an enlarged version of the G36’s transparent magazine, except without the pins for holding more than one magazine together.
Purchasers of the HK417 have typically intended it to complement lighter assault rifles chambered for less powerful intermediate cartridges (often 5.56×45mm NATO), for the designated marksman role. The HK417’s greater accuracy, effective range, and penetration offset its greater expense, its lower rate of fire, and its smaller ammunition capacity both in magazine and carriage
Military and law enforcement
The HK417 models chambered for 7.62×51mm NATO available to the military and law enforcement market are:
- HK417 12″ ‘Assaulter’: carbine with 304.8 mm (12 in) standard barrel
- HK417 16″ ‘Recce’: “Recon” rifle with 406.4 mm (16 in) standard or accurized barrel
- HK417 20″ ‘Sniper’: “full size” rifle with 508.0 mm (20 in) accurized barrel
The HK417A2 is the improved version. The design of the receiver, barrel interface, gas port and the bore axis alignment of the rifle have been further optimised to increase its accuracy and reliability. The German Army uses the HK417 A2 – 13″ with the designation G27.
As of 2013, the HK417A2 models chambered for 7.62×51mm NATO available to the military and law enforcement market are:
- HK417A2 – 13″: carbine with 330.2 mm (13 in) barrel
- HK417A2 – 16.5″: rifle with 419.1 mm (16.5 in) barrel
- HK417A2 – 20″: “full size” rifle with 508.0 mm (20 in) barrel
In April 2016 Heckler & Koch confirmed that a lighter version of the G28 had won the United States Army‘s Compact Semi-Automatic Sniper System contract to replace the M110 Semi-Automatic Sniper System. It is designated as the M110A1 and uses an aluminum upper receiver instead of steel to meet weight requirements, weighing 8.4 lb (3.8 kg) unloaded and reaching some 15 lb (6.8 kg) loaded and with accessories; the M110A1 features a Geissele M-LOK rail handguard, Schmidt & Bender 3–20×50 PM II Ultra Short telescopic sight, Geissele optic mount, OSS SRM6 suppressor, 6-9 Harris bipod and mount, and a collapsible stock with adjustable comb. In May 2018, the U.S. Marine Corps will begin receiving the CSASS, also to replace the M110.
In March 2018, the Army announced that a version of the G28/M110A1 would be issued to infantry squads as the service’s standard Squad Designated Marksman Rifle (SDMR). Issuing a 7.62×51mm NATO SDMR is meant to increase individual squads’ ability to defeat enemy body armor that standard 5.56×45mm NATO rounds cannot penetrate. The M110A1-based rifle will replace the M14 EBR, in use by the Army since 2009, but because it was based on an operational needs statement it had to be turned in by units at the end of a combat deployment. Unlike the sniper configuration, the SDMR model will be equipped with a different buttstock and barrel twist than the CSASS model. The marksman version is fitted with a simpler SIG TANGO6 1-6×24 telescopic sight to make quick adjustments between 0–600 m (0–656 yd), and it fires M80A1 Enhanced Performance Rounds or XM1158 Advanced Armor Piercing Rounds rather than sniper rounds; it will be fielded with a suppressor to make the marksman less identifiable with louder 7.62×51mm NATO rounds. The SDMR TANGO6 1-6×24 telescopic sight features a red horseshoedot for fast aiming and an illuminated Extended Range Bullet Drop Compensation (BDC) illuminated front focal plane reticle. Roughly 6,000 are planned to be fielded with one per squad in infantry, engineer and scout formations. U.S. Army combat units began receiving the first M110A1 SDMRs in April 2020.
|Width||78 mm (3.1 in)|
|Action||Gas-operated short-stroke piston, rotating bolt|
|Rate of fire||600 rounds/min|
|Effective firing range||
|Feed system||10- or 20-round detachable box magazine|