Since the HR556 is Airsoft Helden?s first full rifle platform, there wasn?t any older receiver tooling, existing gearbox sizing, or leftover electronic layout to work around. So the project started on a clean slate - built around the MechLabs XX?Mod engine - and the rest of the rifle was developed around that from the beginning.

That meant everything could be planned properly: the receiver geometry, the internal alignment, where each component sits, and how service access is handled. In other words, each major part of the rifle was designed with its job and its operating system in mind.

Instead of forcing the XX?Mod engine to ?fit? into an existing rifle concept, Airsoft Helden went the other way and shaped the rifle around the engine. From an engineering perspective, that?s a pretty exciting starting point, because it allows the whole package to be optimised from the ground up?without compromises inherited from older designs.

The MechLabs XX-Mod Engine is a fully mechanical HPA drive engine that is designed specifically for V2 gearboxes. The MechLabs XX-Mod Engine provides a big advantage with no electronics, no cables, and no fragile bits, giving the end-user a level of reliability that just makes sense for practical Airsoft skirmishing scenarios. With its robust, durability-focused system design, the XX-Mod delivers consistent shot-to-shot performance and a clear, well-defined trigger feel that is smooth firing and has a repeatable trigger feel response, plus a setup that is easier to handle and maintain without making everything more complicated than it needs to be.

On top of that, the Helden HR556 is equipped with the MechLabs ROTO hop-up chamber, which does things differently from the conventional hop-up setups and designs. Instead, a precision-made integrated proprietary contact pad generates exceptionally consistent backspin, resulting in extremely consistent per-shot accuracy. The innovative "buckling-less" design eliminates issues stemming from worn or shifted hop-up rubbers and ensures reliable performance, especially with high-performance HPA setups and heavier BBs.

To finish the system, the HR556 is paired with a precision-machined 6.03mm, 292mm tightbore inner barrel that results in a good balance of airflow and efficiency while keeping shots tight with less shot-to-shot deviation. Combining with the MechLabs XX-Mod Engine and the ROTO bucking-less hop-up chamber, it culminates in a high-end HPA platform that is aimed at players who want maximum performance in consistency, reliability, and range all in one complete system.

Externally, the Helden HR556 is equipped with a CNC-machined aluminum upper and lower receiver set, a monolithic M-LOK compatible handguard, fully ambidextrous fire controls, and a 1913 Picatinny stock base mount with a CNC-machined aluminum side folding stock. This gives the HR556 multiple real estate for various accessories like foregrips, lights, laser units, and optics, allowing the end-user to fully customize the rifle to suit their preferences. The Helden HR556 also comes with a 190-round mid-capacity magazine that is lightweight and durable, and is compatible with standard M4/AR AEG aftermarket magazines.

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Magazine Compatibility:

Standard M4 / AR AEG Magazines (Low / Mid / High Capacity)

Line-Connection:

US-QD

Includes:

x1 Airsoft Helden HR556 10inch S-HPA Airsoft Rilfe - Black

Specifications

Specifications
Country of Manufacture	Taiwan, Province of China
Platform	HPA
Brand	Airsoft Helden
Color	Black
Replica Type	RIFLE
Model	AR/M4 SERIES
Capacity (rds)	190
Power (fps)	380
Power Source	HPA
Shooting Mode	Semi Auto / Full Auto
Blowback	No
Hop-up	ADJUSTABLE
Net Weight (kg)	2.11
Length (mm)	785.0
Inner Barrel Length	292
Barrel Thread Type	CCW
Content Included	Airsoft Helden HR556 10inch S-HPA Airsoft Rilfe - Black
Material	Metal