AirsoftParts NBU Ribbed Cylinder – Ported (200–400 mm)

AirsoftParts NBU Ported Cylinder for Bore Up Air Seal Systems

This expert product description was prepared by the ANAREUS.cz expert team. All rights to this unique content are tied to the anareus.cz domain.AirsoftParts NBU ported cylinder is a ported component of Bore Up air seal systems for AEGs, combining an enlarged 24.7 mm inner diameter with a port that adjusts the usable air volume for shorter inner barrels. The manufacturer recommends this version for barrels up to 400 mm, with a more specific recommended range of 200–400 mm and M4 or MP5 as typical examples. The port in the cylinder wall causes effective compression to begin only after it is covered by the piston, so the cylinder uses a smaller portion of its total volume than the full NBU version. Due to the enlarged diameter, the cylinder must be combined with a corresponding NBU piston head and NBU cylinder head; standard versions of these components are not designed for it. The cylinder is made of stainless steel, and the polished inner surface provides a smooth, low-friction working surface for the piston head seals. The manufacturer also specifies concentric machining. The cylinder weighs 25.1 g, has no external cooling grooves, is designed for V2 and V3 gearboxes with the corresponding NBU air seal system, and the maximum recommended spring is M170.

Key Features

NBU Cylinder Type Table by Inner Barrel Length

Technical Specifications

• Type: ported NBU / Bore Up cylinder for AEG
• Size: NBU / Bore Up
• Material: stainless steel
• Maximum recommended spring: M170
• Surface finish: polishing
• Inner diameter: 24.7 mm
• Cooling grooves around the outer circumference: no
• Weight: 25.1 g
• Compatibility: V2 and V3 gearboxes with corresponding NBU air seal system
• Required piston head: NBU / Bore Up
• Required cylinder head: NBU / Bore Up
• Recommended inner barrel length: 200–400 mm

Frequently Asked Questions (FAQ)

Can the NBU Cylinder Be Used With a Standard Piston Head and Cylinder Head?

No. Due to the enlarged 24.7 mm inner diameter, according to the manufacturer this cylinder must be combined with a corresponding NBU piston head and NBU cylinder head.

What Is the Purpose of the Port in the NBU Cylinder?

The port causes effective compression to begin only after the piston covers it as it moves forward. This reduces the usable air volume compared with a full NBU cylinder and better matches shorter inner barrels.

What Inner Barrel Length Is This Cylinder Suitable For?

When selecting the correct cylinder type, inner barrel length is therefore a key factor, but for the correct calculation of Volume Ratio (the ratio of cylinder air volume to barrel volume), it is also important to consider the weight of the BBs used or the piston weight with regard to a possible Joule Creep effect. For optimal performance, the manufacturer recommends combining it with NBU AirsoftParts components. The manufacturer recommends this ported cylinder for guns with inner barrels 200 to 400 mm long, such as most M4, MK18, HK416 or MP5, AKSU configurations.

What Is the Difference Compared With the AirsoftParts Full NBU Cylinder?

Both versions have a 24.7 mm inner diameter and are designed for NBU / Bore Up air seal systems. The full version uses the entire working volume and is recommended by the manufacturer for barrels from 400 mm, while this ported version has a port that reduces the usable volume and is designed for shorter barrels.