Abstract: A breach apparatus is provided for breaching a closure or other obstacle. The breach apparatus includes a body forming a cavity, an end cap attached adjacent a first end of the body and a manifold attached adjacent a second end of the body and in fluid communication with the cavity, a ram assembly including a ram head attached to a first end of a battering shaft, a battering piston attached to a second end of the battering shaft within the cavity of the body, a mass piston movable within the cavity of the body between the manifold and the battering piston, a trigger mechanism in communication with the manifold, and a supply tank in fluid communication with the manifold.