This is a special piston designed by the airsoft geniuses at G&P for the Classic Army and A&K CA25 and SR25. The SR25 is a long range sniper rifle with a 7.62mm magazine well. To give the gun more power it has an elongated gearbox with a larger compression unit. This piston is made to be used with upgrades so the user can achieve a higher velocity for more accuracy and more range. This piston will not work in regular length gearboxes.
The use of aftermarket airsoft parts is not an exact science. Some parts may require fitting even thought they were designed to fit without modification. Professional installation of upgrade parts is highly recommended.
I have been using this piston with a Guarder sp160 spring (I'm hitting about 510-520 fps) and an 11.1 LiPo battery in my A&K SR-25 with great results. 8,000 rounds later this thing barely has any damage to it. One thing you want to do before you use it is to shave off the 2nd tooth and if you feel like it go ahead and take out the 3rd one too. You should also check your angle of engagement before you close up your gearbox. The piston head did not last long at all despite the fact that I installed a sorbothane pad onto the cylinder head. Well I guess that is to be expected when your using a sp160. This is off topic but if you buy the A&K SR-25 shim it before you use it or you'll be sorry.
1. Nice and durable.
2. It is not made out of metal/aluminum so it is easier on your gears also you save weight.
3. It does what it is supposed to do.
1. The piston head doesn't endure with high power springs.
Disclaimer: All airsoft guns are required to have the tip (1/4 inch) of the barrel permanently colored in blaze orange. No person may openly display or expose any imitation firearm (replica firearm), in a public place. The term "public place" means an area open to the public or exposed to public view and includes streets, sidewalks, bridges, alleys, plazas, parks, driveways, parking lots, automobiles, whether moving or not, and buildings open to the general public, including those that serve food or drink, or provide entertainment, and the doorways and entrances to buildings or dwellings and the grounds enclosing them. Any person who changes, alters, removes, or obliterates any coloration or markings that are required for by any applicable state or federal law or regulation, for any imitation firearm (replica firearm), or device in any way that makes the imitation firearm (replica firearm) or device look more like a firearm is guilty of violating the state or federal law. By accessing the Site, you certify that you are older than 18 years of age or the age of majority where you live, whichever is older; that you are the owner of any credit card used to purchase on items on the Site; that you are familiar with all local laws in your area affecting your legal right to access airsoft products; that any products you buy are for your own private enjoyment and that you will NEVER share these products with a minor in ANY WAY.