This CNC machined piston head is designed to replace the standard E-12 / E-16 cup-seal in KSC & KWA gas blow back pistols and SMGs with a 15mm cylinder in the loading nozzle. A high quality O-ring on a precisely machined POM body is used to provide a better and more reliable seal than worn or poor fitting cup-seals which can increase gas efficiency and in some cases fps.

Each piston head is machined from Acetal (POM), a lightweight and durable plastic to a tight tolerance and includes 3 spare O-rings (4 in total) ready for future replacement and a stainless steel Torx screw.

Compatible with the following KSC S7 & KWA NS2 GBBs

USP, USP Compact, P226r, M226, M11A1, Cz75, Kz.75


Caution – KSC & KWA GBBs normally have threadlocker applied to the screws in the blow back unit, care should be taken when removing them for the first time to avoid rounding off screw heads, a small amount of silicone oil or grease should be applied to the O-ring during installation.