Acheron KWS Rail System SG 550


Our KWS Rail System for the SG 55x rifle family has been engineered to provide a stable platform for the attachment of accessories. In comparison to conventional handguards, the Acheron KWS Rail System connects to the host weapon without any wiggle. This enables the use of rail-mounted nightvision and laser aiming devices without point-of-impact shift caused by handguard movement. This upgrade adapts these rifles to modern requirements and greatly enhances their combat value.

The top rail complies with both the NATO standard STANAG 4694 and the American standard MIL-STD-1913.

M-LOK slots facilitate the attachment of accessories like weaponlights or foregrips and allow for excellent air circulation.

Machined from high-strength aluminium, the KWS Rail system is both strong and lightweight. A hard coat anodized finish provides excellent resistance to wear and corrosion.


Fits current issue Swiss military rifles (Stgw 90 / Fass 90) including the civilian semi-auto variant (PE90) as well as any other SG 550 with diopter sights.
The height of the top rail sits flush with the following retrofit rails clamped to the receiver:

  • B&T Low Profile Mount (Art. Nr. BT-20120-2)

Designed, manufactured, finished and assembled in Switzerland.

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Facts & Figures

Additional information


498 g

Mounting Standard



7075-T6 / 1.7227

Surface Finish

Type III Anodized / QPQ Tenifer

Color options



CHF 595*

Part Number


* Swiss VAT included, price only valid in Switzerland. Depending on local currency exchange and tax rates, prices may vary in other countries.


Available on backorder

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