HPA Adapters for SMC9 & GTP9 Pistols

Question:

Can I run my Agency Arms SMC9 or GTP9 on HPA, and what performance changes should I expect compared to green gas?

Answer:

Yes. The SMC9 and GTP9 share the same G-series magazine footprint, so a dedicated HPA adapter replaces the magazine base plate and feeds gas directly into the magazine's valve. This eliminates the need for a gas reservoir inside the mag, which is the primary source of cooldown inconsistency on green gas.

Question:

Does the adapter require permanent modification to the magazine?

Answer:

No. The adapter installs by removing the factory base plate — typically two screws — and bolting the HPA base in its place. An internal O-ring seals against the magazine body. The process is reversible in minutes; you can swap back to green gas for indoor CQB where fields ban HPA tanks or regulators.

Question:

What pressure should I run, and do I need a specific regulator?

Answer:

Start at 100–120 PSI on a standard 800 PSI output HPA tank with a adjustable regulator (e.g., Wolverine Storm, PolarStar MRS, or Redline SFR). The SMC9/GTP9 cycle reliably in this window. Higher pressures increase FPS and cyclic rate but accelerate wear on the nozzle return spring and hammer/sear engagement surfaces. Chronograph after every 10 PSI adjustment.

Question:

Will I lose the bolt hold-open function?

Answer:

No. The adapter feeds gas through the magazine's existing fill valve port. The follower and bolt catch mechanism remain untouched. Last-round lockup functions exactly as it does on green gas, provided the magazine spring and follower are in good condition.

Question:

Where can I find a drop-in adapter for these platforms?

Answer:

Primary Airsoft (https://primaryairsoft.us/) stocks a dedicated SMC9/GTP9 HPA adapter machined for the G-series magazine profile, plus spare O-rings, feed tubes, and M4 magazine releases if you pair it with an M4-mag-fed lower. The same adapter also fits Glock/AAP-01 and G-series/AAP-01 magazines, so one purchase covers multiple pistol platforms.

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.