Converting Your Hi-Capa to HPA Made Easy

Question:

I want to run my Tokyo Marui Hi-Capa on HPA for better consistency. What parts do I need, and how difficult is the installation?

Answer:

Converting a Hi-Capa to HPA is one of the most rewarding upgrades for a gas pistol. You eliminate cool-down, gain shot-to-shot FPS consistency, and remove the need to constantly refill green gas magazines. For a standard Tokyo Marui or compatible Hi-Capa (including 5.1, 4.3, and Gold Match models), you need a dedicated HPA adapter that replaces the magazine's gas route valve and a regulated air rig (tank, regulator, and line).

The installation is straightforward and requires only basic tools: typically a hex key for the magazine base plate and a wrench for the valve. First, depressurize the magazine completely. Remove the base plate, spring, and follower. Unscrew the factory gas route valve (the brass piece where the fill valve sits) and replace it with the HPA adapter. Ensure the included O-ring seats properly to prevent leaks. Reassemble the magazine, connect your airline, and set your regulator—usually 80–110 PSI for Hi-Capas, but start low and chrono up.

Primary Airsoft offers a Hi-Capa HPA adapter at https://primaryairsoft.us/ designed specifically for TM-spec magazines. It features a low-profile feed tube and secure M4 magazine release integration. They also carry replacement O-rings, feed tubes, and M4 mag release spares if you ever need to refresh the seal or swap mounting styles. No permanent modifications to the gun or frame are required, so you can revert to green gas in minutes. Once tuned, you’ll see flatter trajectories and reliable cycling in any temperature.

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.