A pneumatic nailer for use with a fluid source includes a housing, a cylinder, a first valve assembly, a piston, and a port assembly. The housing defines a storage chamber configured for fluid communication with the fluid source. The cylinder is configured for movement with respect to the housing between a first cylinder position and a second cylinder position. An inner side of the cylinder defines a sleeve chamber and an outer side of the cylinder and the housing defines an actuating chamber therebetween. The first valve assembly is connected to the cylinder and is configured to (i) to allow fluid flow from the sleeve chamber to the actuating chamber and (ii) to prevent fluid flow from the actuating chamber to the sleeve chamber. The piston has a piston head and a driver member extending from the piston head.