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ZCI 16.5T Extended Half-tooth Aluminum Piston


These pistons are made for extended gearboxes like those found in SR-25s and L85s. They have a lightened aluminum frame and a steel gear rack. These are the half tooth version which while can be used fine with normal gearsets also have the ability to work with high torque gearsets where the sector gear teeth extend too far like that of 32:1 gearsets. Aluminum pistons are normally significantly heavier than their polymer counterparts and this has some positive and negative effects. Heavier pistons normally have a positive effect on FPS and a slight negative effect on ROF. This effect is much more pronounced with the use of heavier rounds so these work well with super heavy sniper rounds. Heavier pistons also put more stress on the gearbox due to higher impact energies which can cause gearbox cracking if steps aren't taken to prevent is like raidusing, sorbo, and STSs. In total I would recommend these be used with care, they can be very durable and effective when used properly. These are ideally suited for use in high power DMRs using heavy rounds and long barrels. The added volume from the extended gearbox provides more air for a longer barrel and heavier rounds. It's added mass provides the momentum to use that air with heavy rounds and it's ability to use high torque gearsets means you can easily utilize very stiff springs without overloading the motor and electrics.

Material: Aluminum body and steel rack
Number of steel teeth: 16.5 + pickup block
Piston mass: 24.15g ( .852oz)
Guide rail pattern: solid rail
Stock Piston head lock hole: No

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  • Model: M-156b
  • Shipping Weight: 0.1304lbs
  • 3 Units in Stock
  • Manufactured by: ZCI

This product was added to our catalog on Wednesday 03 February, 2016.