Lancer Tactical Airsoft 8-Hole Flat Aluminum Piston Head w/Bearing, Blue

It's a simple part, but it's one of the places where a worn gearbox starts leaking air and losing consistency. This is Lancer Tactical's 8-hole flat piston head, made from aluminum alloy and finished blue. It's designed to replace a stock piston head on the AEG gearbox — typically the Version 2 shell used in M4, MP5, G3, and similar platforms — and to give you two things a replacement head doesn't: an embedded bearing for smoother travel, and eight holes that reduce air resistance during the piston's forward stroke.

Why the 8 holes matter. On a standard solid piston head, the cylinder has to push a solid disk of air out of the way as the piston accelerates forward. That resistance slows the piston's travel, eats a bit of energy, and adds wear on the nozzle seal. The 8 holes let that air escape around the piston head itself, so the piston hits the nozzle seal harder and faster. Harder hit means a better seal on the shot, which translates to more consistent velocity and less air waste.

The bearing. The bearing sits inside the piston head and rides against the cylinder wall. It takes the friction that a plain plastic or nylon piston head pushes entirely on its O-ring and the cylinder wall. Less friction means the spring's energy goes into pushing air down the barrel rather than fighting drag, and it extends the life of both the piston and the cylinder wall. You still want decent shimming and a clean cylinder wall, but the bearing makes the whole system happier over time.

Material and build. Aluminum alloy construction is lighter than cast zinc and far more durable than the plastic heads most stock guns ship with. The blue finish is cosmetic and corrosion-resistant; it doesn't change how the part works. Weight is 11.2 grams, which is standard for a full-size AEG piston head. Fits Version 2 gearboxes — the shell used in most M4-pattern, MP5-pattern, and G3-pattern AEGs. If your gearbox is a different shell version (V3, V6, V7), this won't fit.

Before you install. A piston head doesn't live in isolation. Check the piston head O-ring while you're in there — a worn O-ring is the single most common cause of inconsistent velocity regardless of what the piston head is made of. Also inspect the nozzle seal and the cylinder head O-ring; replace them if either is flattened or cracked. Good shimming on the gears makes a quiet, efficient gearbox. If the cylinder wall has deep grooves from a worn piston, a new piston head won't fix the consistency problem — the cylinder itself may need to be replaced.

What else to know. This is an internal upgrade part. It doesn't fire, shoot, or change velocity on its own — it works as part of the gearbox assembly to improve air seal and reduce drag. If your gun's velocity is inconsistent shot to shot, a worn piston head is one of the likely causes, but so are a tired nozzle seal, cracked O-rings, and bad shimming. The fix is usually all of them at once.

One aluminum piston head with the integral bearing. No O-rings, seals, or tools included.