Uploaded May 2026 | Updated September 2026, 2 weeks ago
In this video, we walk you through the complete process of removing the HPA gearbox from your MDRX and replacing the nozzle, then reassembling the rifle.
The MDRX HPA system is designed to be adaptable to a wide range of power configurations thanks to interchangeable nozzles with different airflow levels.
Factory configuration:
Complete MDRX HPA rifles are shipped with a 1-hole nozzle (20% airflow) installed
→ This limits power below 2 joules to comply with Hong Kong regulations
A 2-hole nozzle (40%) and a full-flow / 6-hole nozzle are included in the box
Standalone HPA engines are delivered with the full flow nozzle installed, and a 2-hole nozzle as spare
Nozzle selection guide:
For best accuracy and efficiency, always use the least restricted nozzle for your target power level:
1-hole (20%) → bellow 1 Joule
2-hole (40%) → 1.0 to 1.4 Joule
6-hole / full flow (100%) → above 1.4 Joule
Please note that longer barrel configurations generate more power: MDRX 16" will produce higher energy than the Micron (10.5") with the same settings. Heavier BBs increase Joule Creep and improve efficiency. Lower pressure generally improves consistency and accuracy.
Important:
Maximum recommended operating pressure: 8 bar
Staying within this limit will help ensure long-term reliability and durability of the solenoid valve.
This tutorial covers:
Safe removal of the HPA gearbox
Nozzle replacement procedure
Correct reassembly of the rifle
Music:
Beginnings - Unicorn Heads
Smile - Jeremy Blake
The Machines Dream - South London HiFi
In this video, we walk you through the complete process of removing the HPA gearbox from your MDRX and replacing the nozzle, then reassembling the rifle.
The MDRX HPA system is designed to be adaptable to a wide range of power configurations thanks to interchangeable nozzles with different airflow levels.
Factory configuration:
Complete MDRX HPA rifles are shipped with a 1-hole nozzle (20% airflow) installed
→ This limits power below 2 joules to comply with Hong Kong regulations
A 2-hole nozzle (40%) and a full-flow / 6-hole nozzle are included in the box
Standalone HPA engines are delivered with the full flow nozzle installed, and a 2-hole nozzle as spare
Nozzle selection guide:
For best accuracy and efficiency, always use the least restricted nozzle for your target power level:
1-hole (20%) → bellow 1 Joule
2-hole (40%) → 1.0 to 1.4 Joule
6-hole / full flow (100%) → above 1.4 Joule
Please note that longer barrel configurations generate more power: MDRX 16" will produce higher energy than the Micron (10.5") with the same settings. Heavier BBs increase Joule Creep and improve efficiency. Lower pressure generally improves consistency and accuracy.
Important:
Maximum recommended operating pressure: 8 bar
Staying within this limit will help ensure long-term reliability and durability of the solenoid valve.
This tutorial covers:
Safe removal of the HPA gearbox
Nozzle replacement procedure
Correct reassembly of the rifle
Music:
Beginnings - Unicorn Heads
Smile - Jeremy Blake
The Machines Dream - South London HiFi
