EXPECTED DATE OF RELEASE - LATE JUNE 2026
The MDRX HPA Conversion Kit allows you to convert your MDRX AEG into an electro-pneumatic HPA-gun.
Built around a simple and extremely robust open-bolt HPA architecture, the MDRX HPA engine was designed to provide excellent reliability, outstanding feeding consistency, wide power adjustability, and very high rate of fire capability while keeping maintenance requirements to a minimum.
Kit Contents
The kit includes:
MDRX HPA Engine
2x mounting screws (M4x12 ISO14581)
HPA airline with male PCP fitting
FCU and wiring set
MDRX HPA hop-up chamber
Silverback SRS/TAC-41 80° hop-up rubber
6-hole / Full Flow nozzle pre-installed and 2-hole nozzle included as spare part
HPA Engine
The MDRX HPA system is based around an industrial-grade 3V110-06 NCF 3/2 solenoid valve powered by 12 V DC. This industrial valve architecture provides extremely high reliability, low maintenance requirements, and an affordable price.
In our HPA engine, the airflow used to propel the BB does not pass through the solenoid valve itself. The valve only controls the movement of the nozzle:
When energized, air pressure pushes the nozzle forward and chambers a BB
Once deployed, air flows directly through port(s) machined into the nozzle itself to propel the BB
The nozzle movement is entirely pressure driven, with no return spring and only one moving part.
The pneumatic assembly contains only 4 parts and 5 seals, including only 3 dynamic FKM/Viton seals. The nozzle itself is manufactured from POM to reduce friction, reduce mass, and avoid damaging BBs.
When the valve is deactivated, the air used to actuate the nozzle is vented directly inside the lower receiver through the valve exhaust port. Because propulsion airflow bypasses the valve entirely, the valve flow rate does not limit the maximum achievable power.
Pressure Range & Performance
The system operates between 4 and 8 bar (58 to 116 PSI). However, the best accuracy and consistency are generally achieved at lower pressures, typically between 4.5 and 6.5 bar (65 to 94 PSI).
For this reason, Silverback recommends:
Using the least restrictive nozzle possible
Using heavy BBs whenever possible
The system benefits significantly from Joule Creep with heavy BBs.
The MDRX HPA is capable of:
Up to 40 BBs/s with ease
Up to 50 BBs/s with advanced tuning and higher operating pressures
Nozzle Configurations
Three nozzle configurations are available:
1-hole nozzle
Optimized for sub-1 Joule configurations.
2-hole nozzle
Recommended for 1 to 1.4 Joule configurations.
6-hole / Full Flow nozzle
Recommended for configurations above 1.4 Joules.
HPA kits are delivered with the 6-hole / Full Flow nozzle pre-installed and the 2-hole nozzle included as spare part.
Users are responsible for complying with local laws and power limits.
HPA-Specific Hop-up System
The MDRX HPA uses a dedicated hop-up chamber specifically developed for this pneumatic system. A built-in feeder guides BBs directly toward the front face of the nozzle, ensuring extremely reliable feeding, perfect BB alignment, and complete elimination of double-feeds and misfeeds.
The HPA engine and hop-up chamber are designed to self-align with each other for maximum consistency.
The chamber accepts standard AEG-type hop-up buckings, however Silverback strongly recommends using SRS/TAC-41 type buckings for optimal air seal performance.
All MDRX HPA kits are factory-equipped with a Silverback SRS 80° hop-up rubber. A harder bucking provides improved stability and consistency with this HPA architecture.
Air & Battery Consumption
Under optimal conditions, the system is capable of approximately 2000 to 2500 shots using a 0.8 L / 48 ci air tank filled to 207 bar / 3000 PSI.
The system requires one 11.1 V LiPo stick battery. A 1200 mAh battery typically provides enough capacity to empty several air tanks.
Fire Control Unit (FCU)
Developed in collaboration with T238, the FCU allows adjustment of:
Fire modes (safe / semi / 3 to 5 BBs burst / full auto / binary)
Dwell setting (0.5 ms increments)
ROF adjustment (12 to 50 BBs/s)
DMR cool-down timer (0.5 to 5 s or disabled)
Battery protection level (3.3 to 3.0 V/cell or disabled)
Sleep timer (1 to 10 h or disabled)
Additional FCU functions include current program readback, total BB counter, daily BB counter, factory reset, and daily counter reset.
