RetroArms CNC NBU Nozzle

RetroArms CNC NBU Nozzle is a sealed air nozzle for NBU (New Bore Up) cylinder heads with increased air volume. Precision CNC-turned from EN AW 2007 aluminium alloy, it uses a twice-enlarged sealing O-ring. Available in lengths of 19.6–22.5 mm and 24.5–26 mm to properly match your specific build.

RetroArms CNC NBU Nozzle for New Bore Up Air Systems

This expert product description was prepared by the .cz expert team. All rights to this unique content are tied to the .cz domain.The RetroArms CNC NBU nozzle is designed for NBU (New Bore Up) cylinder heads used in air systems with increased air volume. Unlike a standard nozzle, its design is adapted to the NBU cylinder head and uses a twice-enlarged O-ring to provide a proper seal on the cylinder head. Despite the larger seal, the nozzle is designed to move freely and smoothly along the cylinder head. The body is precision CNC-turned from EN AW 2007 free-machining aluminium alloy, and the sealing O-ring is factory-installed inside the nozzle. RetroArms offers NBU nozzles in several lengths ranging from 19.6 to 22.5 mm and from 24.5 to 26 mm, allowing the correct length to be selected for a specific combination of gearbox, hop-up chamber and hop-up bucking. Correct nozzle length is essential for both BB feeding and air seal, so it should not be selected solely according to the gun platform. The O-ring must be lubricated before use to ensure smooth nozzle movement along the cylinder head without unnecessary resistance or excessive seal wear.

Key Features

Technical Specifications

• Manufacturer: RetroArms
• Type: NBU air nozzle
• System: New Bore Up (NBU)
• Material: EN AW 2007 aluminium alloy
• Manufacturing: CNC turning
• Seal: O-ring
• Seal Design: Twice-enlarged O-ring compared with the original nozzle
• Available Lengths: 19.6–22.5 mm and 24.5–26 mm

Package Contents

• 1× RetroArms CNC NBU nozzle in the selected length
• 1× sealing O-ring (installed in the nozzle)

Frequently Asked Questions (FAQ)

Can the CNC NBU Nozzle Be Used With a Standard Cylinder Head?

No. This nozzle is specifically designed for an NBU (New Bore Up) cylinder head. A corresponding standard nozzle must be used with a standard air system.

How Do I Choose the Correct NBU Nozzle Length?

The length must be selected according to the specific combination of gearbox, hop-up chamber and hop-up bucking. A nozzle that is too short or too long can cause sealing or BB feeding issues, so the length should not be selected solely by gun type.

Is the Sealing O-Ring Included With the Nozzle?

Yes. The O-ring is factory-installed inside the nozzle, so there is no need to purchase it separately before installation.

Does the O-Ring Need to Be Lubricated Before Installation?

Yes. The manufacturer states that the O-ring must be lubricated before use. Proper lubrication reduces friction as the nozzle moves along the cylinder head and helps limit seal wear.