We have several upgrade pistons in our range. For well-known brands such as the VSR 10, Silverback SRS, Tac-41 and the L96 from action army.
An upgraded piston provides better compression in your Sniper Rifle cylinder. Upgrading this will give you more consistent shot-to-shot accuracy and may increase your Joule output. Snipers often shoot a bit low in joules/fps from the factory.
In addition, an aluminum piston is often lightweight and because it is produced accurately, it provides a better performance than a standard piston made of plastic.