HPA Adapter WE M4 to M4

A modular HPA adapter that converts compatible WE Open Bolt GBB rifles to use an external HPA system with Airsoft M4 AEG magazines.

Product Features:

• Compatible with WE Open Bolt M4, SCAR-L, 416 and other WE Open Bolt rifle platforms.
• Compatible with Airsoft M4 AEG magazines.
• Plug and play installation with valve, feed lips and gas router pre-installed.
• Injection moulded polycarbonate M4 magazine well.
• NBR rubber gas router.
• Includes interchangeable magazine fitment shims.
• Supplied with a US Foster HPA quick disconnect fitting.
• Compatible with interchangeable AIRTAC modular magwells.
• Recommended operating pressure: 90-150 PSI.
• Maximum operating pressure: 150 PSI.
• Integrated BB retention system to minimise BB loss during magazine changes.

The AIRTAC WE M4 to M4 HPA Adapter is a modular conversion adapter designed for compatible WE Open Bolt gas blowback rifle platforms. It replaces the standard gas magazine with an adapter that allows the replica to be powered by an external High Pressure Air system while feeding from Airsoft M4 AEG magazines.

Designed as a plug and play solution, the adapter is supplied with the valve, feed lips and gas router already installed, removing the need to transfer components from an existing magazine. Magazine fitment shims are included to help optimise magazine compatibility across a wide range of Airsoft M4 AEG magazines.

The modular construction allows the magazine well to be exchanged for other AIRTAC magwell configurations, providing additional flexibility without replacing the complete adapter. An integrated BB retention system helps reduce BB loss during magazine changes, while the supplied US Foster quick disconnect fitting provides a standard HPA connection.

The adapter is intended for operation between 90 and 150 PSI, with a maximum operating pressure of 150 PSI.

Range Overview:

AirTac’s HPA Adapters range converts traditional gas-powered replicas to use high-pressure air magazine systems with seamless reliability. Designed for multiple replica platforms, each adapter features precision-moulded construction, a secure BB-retention system, and standardised US-thread fittings for broad compatibility. The range combines rugged strength with practical installation, giving players smoother reloads and extended playtime through improved air efficiency and modular flexibility.

• Injection-moulded polymer housings provide durability and consistent alignment
• Standard US-thread fittings ensure cross-system HPA compatibility
• Integrated BB-retention systems prevent feed loss during reloads
• Supplied with magwell inserts, screws and shim sets for precise fitment
• Available for multiple pistol and SMG platforms for modular loadouts
• Engineered for reliability, consistency and long-term performance

Brand Statement:

AirTac specialise in developing high-performance HPA conversion systems for airsoft enthusiasts seeking consistent, efficient, and adaptable performance. Their focus on precision engineering and robust construction ensures every product delivers dependable field use, intuitive function, and lasting value.

Safety Information:

Do not exceed 150 PSI when operating any airsoft HPA adapter Always use air regulated by a secondary regulator Check PSI output before connecting air to the adapter Do not connect directly to unregulated air sources, CO2 systems, or high-pressure tanks Do not use with incompatible high-pressure air lines or fittings Always ensure correct setup and operation before use