Cylinder (Inner Barrel Length 301-400mm)

Correct air volume for 301-400mm barrels

The ASG Ultimate cylinder for 301-400mm inner barrels uses a ventilation hole positioned to match that barrel range. Getting the vent position right for your barrel length is one of the simplest ways to keep compression efficient and consistent shot to shot, so the volume of air behind the BB is properly matched to the bore it has to travel down.

Seamless steel construction

Each tube is made from 45C cold-drawn seamless steel with a Rockwell hardness of 20-25. The cold-draw process produces a smooth inner surface and a tight, consistent bore, while the hardness reduces the risk of the cylinder deforming when it is pressed into the gearbox during installation.

Isonite finish and heat dissipation

An Isonite oxide surface treatment gives the black finish its corrosion resistance and low friction properties. The outer surface is CNC-scored into a grooved pattern that increases surface area and helps the cylinder shed the heat that builds up during rapid firing.

TM-standard fitment

The cylinder is built to Tokyo Marui standards, so it drops into most Version 2 and Version 3 gearboxes that use TM-spec internals. It pairs naturally with an ASG Ultimate piston, nozzle and cylinder head for a matched air-seal set. Browse related airsoft accessories to complete the build.

Genuine ASG Ultimate part

This is a genuine ASG Ultimate Upgrade Series component, the internal parts range ASG designed to maintain and optimise AEGs. If you would rather have it fitted, our workshop can install it as part of a service.

Bought from the specialists: our in-house workshop in Rochester, Kent can service, repair and upgrade your kit. See our airsoft gun repair and servicing.