A plug and play HPA adapter that converts compatible M870-style gas shotguns to use an external HPA system with Airsoft M4 AEG magazines.
Product Features:
Compatible with TM M870, Breacher, Golden Eagle and Secutor style gas shotguns.
Compatible with most Airsoft M4 AEG magazines.
Plug and play design with valve, feed lips and gas router pre-installed.
No donor parts or assembly required.
Injection moulded polycarbonate M4 magazine well.
Polished internal magazine well for smoother magazine insertion.
Adjustable side shims reduce magazine wobble.
Reversible side shims provide additional adjustment for wider magwells.
Rear adjustment screw reduces vertical movement of the adapter.
Integrated BB retention system minimises BB loss during magazine changes.
Swappable rear magazine shim included.
Recommended operating pressure: up to 150 PSI maximum.
Supplied with a US Foster HPA fitting.
The AIRTAC M870 Breacher Shotgun to M4 HPA Adapter converts compatible M870-style gas shotguns to operate from an external High Pressure Air system while feeding from Airsoft M4 AEG magazines. Designed for TM M870, Breacher, Golden Eagle and Secutor style platforms, it provides increased ammunition capacity and faster reloads without requiring permanent modification to the shotgun.

Supplied fully assembled, the adapter includes the valve, feed lips and gas router already installed, allowing it to be fitted straight from the box without transferring components from an existing gas reservoir. The injection moulded polycarbonate magwell features polished internal surfaces to promote smooth magazine insertion and reliable operation.

To improve fitment across different shotgun manufacturing tolerances, the adapter incorporates adjustable side shims and a rear adjustment screw. The side shims can also be reversed to provide additional adjustment for wider magwells, while the rear screw reduces vertical movement within the receiver. An integrated BB retention system helps minimise BB loss during magazine changes for more efficient reloading during gameplay.

Designed for compatibility with most Airsoft M4 AEG magazines, the adapter is supplied with a US Foster HPA fitting and should only be operated with a regulated HPA system at a maximum pressure of 150 PSI.