These US Contract overruns are 5.56mm short stroke gas piston-operated Complete Upper Receiver Assemblies manufactured specifically for the HK416 platform. Built to exact government request these uppers delivers the legendary reliability and reduced maintenance of the HK416’s short-stroke gas piston system in a compact 10.5" configuration. Unlike traditional direct-impingement systems, the piston-driven design keeps fouling, carbon, and heat out of the receiver and bolt carrier group, resulting in significantly cleaner operation, longer service intervals, and superior performance in adverse conditions (dust, sand, suppressed use). This US-made assembly is engineered as a true replacement upper for HK416 rifles (and compatible MR556/MR223 platforms) manufactured by highly capable US manufacturers. It features a high-quality 14.5" barrel, full piston operating system, HK-spec bolt carrier group, and accessory capable handguard. It installs directly onto standard HK416 lowers or mil-spec AR15 lowers with no modifications required. Ideal for military, law enforcement, or serious civilian users seeking HK416-level performance in a compact carbine/pistol configuration. Each unit is test-fitted and function-checked for reliability.
Key Benefits
- Short-stroke gas piston system for exceptional reliability and minimal fouling
- Reduced heat and carbon buildup for extended maintenance intervals
- Drop-in compatibility with HK416 / AR15 platform lowers
- US-manufactured to high contract-grade standards
- Ready-to-install complete assembly
Specifications
|
Specification
|
Details
|
|
Caliber
|
5.56x45mm NATO (.223 Remington compatible)
|
|
Operation
|
Short-stroke gas piston (HK416 pattern)
|
|
Barrel Length
|
14.5 inches
|
|
Twist Rate
|
1:7 RH
|
|
Chamber
|
5.56 NATO
|
|
Muzzle Device
|
A2-style flash hider
|
|
Gas System
|
Short-stroke piston, adjustable for suppressed use
|
|
Upper Receiver
|
HK416/MR556 height
|
|
Bolt Carrier Group
|
HK416-spec piston-compatible BCG
|
|
Charging Handle
|
Standard
|
|
Finish
|
Mil-Spec hardcoat anodize (black)
|
|
Compatibility
|
HK416, MR556, and mil-spec AR-15 lowers
|
|
Country of Origin
|
USA (Built to Contract)
|
Included in the Complete Assembly
- Assembled upper receiver with forward assist and ejection port cover
- 10.5" piston-ready barrel with gas block and piston/operating rod installed
- Handguard
- Complete piston bolt carrier group
- Charging handle
This upper provides the proven performance of the HK416 system in a compact package while meeting or exceeding US contract manufacturing standards for durability and reliability.