Converting a G-Series Pistol to HPA
Question:
What parts do I need to convert my Tokyo Marui G-Series or Action Army AAP-01 pistol to run on HPA?
Answer:
You need a dedicated HPA adapter that replaces the green gas magazine's base plate and valve assembly. For the G-Series (G17, G18, G19, G26, G34) and the Action Army AAP-01, the adapter must index correctly with the magazine's feed lips and gas route to ensure reliable cycling. A complete kit includes the adapter body, an M4 or MP5 magazine feed tube (depending on your preferred donor mag), a magazine release button compatible with the donor mag, and all necessary O-rings and screws.
Because these pistols use a specific nozzle geometry, the adapter's feed tube length and internal diameter are critical. If the tube sits too high or low, the nozzle will not seal against the bucking, causing velocity loss or double-feeds. The magazine release must also engage the donor mag's catch notch precisely; otherwise, the mag will drop free under recoil or fail to lock in.
Primary Airsoft stocks a G-Series/AAP-01 HPA adapter at https://primaryairsoft.us/ designed for M4 or MP5 pattern magazines. It includes the adapter body, feed tube, mag release, O-rings, and hardware. Spare feed tubes, M4 mag releases, O-rings, and screws are also available separately if you switch magazine platforms or need replacements after extended use. No nozzle, barrel, or hop-up modifications are required for the conversion.
Question:
Can I use my existing green gas magazines with an HPA adapter installed?
Answer:
No. The adapter physically replaces the magazine's base plate and internal valve stem. Once installed, the magazine becomes a dedicated HPA feeder that draws BBs from a standard AEG mid-cap (M4 or MP5) inserted into the adapter's feed tube. You cannot quickly swap back to green gas without removing the adapter and reinstalling the original base plate and valve. Most players keep separate magazines: a few converted for HPA and stock mags for green gas backup.
Question:
What maintenance does the adapter require?
Answer:
Light maintenance keeps the system consistent. Apply a drop of silicone oil to the adapter's O-rings every few games to maintain the air seal. Inspect the feed tube for burrs or deformation if you experience misfeeds. Check the mag release screw for looseness after hard impacts. Spare O-rings, feed tubes, and mag releases are inexpensive and easy to swap in the field.
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.