The ARES Piston for ARES Spring Power Bolt Action the perfect upgrade or replacement part for you bolt action Ares sniper rilfes. It features elongated ventilated piston head that prevents vacuum behind the BB when you use a long barrel. Fits the following ARES rifles: M40A3, MSR338, MSR700, WA2000, L96, Gun Smiths series, M200, EDM, M40A6.