A hydraulic buffer assembly for use in a paint gun includes a sealed housing having first and second ends and an interior including a chamber containing a hydraulic fluid. A piston assembly including at least one piston rod and a piston head is axially movable through the interior of the housing, wherein the piston head includes at least one orifice through which hydraulic fluid flows when the piston assembly is moved under load. The buffer assembly is configured to decrease or slow the firing rate of an automatic paint gun.