HPA Adapters for Shotgun M4 Mag Feeding
Question:
Can I run M4 magazines in my gas shotgun using an HPA adapter, and which models are supported?
Answer:
Yes, the Primary Airsoft M870 M4 magazine adapter lets you feed standard M4-style AEG mid-caps or high-caps directly into a Tokyo Marui-spec gas shotgun. The kit replaces the factory shell tube with a CNC-machined aluminum receiver block that indexes an M4 mag vertically, using a spring-fed feed tube to push BBs into the shotgun’s loading nozzle. Because the adapter uses the gun’s original gas system to cycle the bolt, you retain realistic pump action while gaining 100–150 rounds per mag instead of 30-shell capacity.
Supported platforms include the Tokyo Marui M870 series (Gas Blowback and Breacher), the Marui M870 Tactical, and compatible clones such as the APS CAM870 and Double Eagle M870. The adapter is not compatible with the Marui SAIGA-12, Krytac Trident MK2 shotgun, or any box-mag-fed platform — those require entirely different magazine wells.
Installation takes roughly ten minutes: remove the stock tube, slide the adapter into the receiver, secure the included set screws, and insert the feed tube. No permanent modifications are required, and the original shell tube can be reinstalled in seconds. The feed tube is user-replaceable (spare tubes and O-rings are available separately) and the M4 mag release lever is also sold as a spare part if the latch tab ever wears down.
If you already run an HPA rig, you can pair this adapter with a green gas nozzle (bottle or hose style) to top off the shotgun’s internal gas reservoir without carrying green gas cans. Primary Airsoft stocks the M870 M4 adapter, green gas nozzles, and all replacement spares at https://primaryairsoft.us/.
Running an HPA or mag-fed setup?
Primary Airsoft makes HPA adapters for Hi-Capa, Glock/AAP-01, MK23/SSX23, SSQ22, 1911, Beretta M9, CZ P09, CZ SP-01, KWA KMP9, KWA MP7, SMC9/GTP9 and more — feeding M4, MP5 or X9 magazines — plus magwells, green gas nozzles and adapter spares. Shop them at primaryairsoft.us.