Abstract: A improved apparatus for decelerating a piston and impacting rod assembly within a single stroke foundry impactor utilizing a non-metallic deceleration piston slidably positioned within a pressurized deceleration chamber mounted proximate the end of the bore containing the impactor piston and impacting rod assembly. The deceleration piston is biased towards the impactor bore by pressurization of the deceleration chamber, such that upon a stroke of the impactor, the residual kinetic energy of the piston and impacting rod assembly is absorbed by the biased deceleration piston.