Description
ACM CNC Piston with Full Steel Teeth
This ACM piston is listed as CNC-made with a full rack of steel teeth. It is a replacement or upgrade piston for AEG gearboxes, made to stand up to the stresses of regular use and uprated springs better than a basic plastic piston.
The piston is one of the hardest-working parts in an AEG gearbox, and a stripped piston is one of the most common failures. Steel teeth along the full length give a durable contact surface for the sector gear.
Why steel teeth
The piston is pulled back by the sector gear, compressing the main spring, and then released to push air through the cylinder and fire the BB. Its teeth take a heavy load on every shot, especially with stronger springs and higher rates of fire.
Steel teeth stand up to that wear much better than plastic, which is why reinforced pistons are a common upgrade when a stock piston has stripped or when the gearbox is being uprated.
Fitting
Fitting this part means opening the gearbox, so it is best suited to players with technical experience or to an airsoft technician. Always remove the battery and magazine first, take photographs as you dismantle, and keep track of small springs and screws, particularly the trigger and anti-reversal latch springs.
After reassembly, test the replica on every fire mode at a safe backstop and have it chronographed before taking it to a game.
Key features
- Listed as CNC-made piston
- Full steel teeth
- Durable replacement for stripped pistons
- Suited to uprated springs
- Affordable ACM component
Compatibility
Piston length, teeth layout and head fitting vary between gearbox versions and makers. Our original listing advises confirming fit with your gearbox before purchase. Check whether your sector gear needs a full rack of teeth or a piston with a tooth removed for correct engagement, and check the piston head fits. If in doubt, contact us with your replica model.
Care and maintenance
Use a proper airsoft gearbox grease, applied sparingly, rather than household oils, which can attract dirt or damage plastic parts. Check moving parts for wear and correct shimming whenever the gearbox is open for servicing.
Keep the replica’s battery in good condition, as a weak battery makes the motor work harder and puts extra load on every part of the drivetrain.
Who is it for?
This piston suits technicians and experienced players replacing a stripped piston or building a stronger gearbox.
Please note: Fitting by an experienced player or technician is recommended. Piston head not mentioned in our listing.
