this building appeared to be strongly built and fairly substantial but regardless of its strength it was now being riddled and shaken to its very foundation ; the unleashing of 2.75 rockets and machinegun fire from the helicopter whirling above was savage but he recognized that noise that wasnt noise , that was pure music that was an od ( olive drab color ) green uh-1d huey , and it was the property of the u.s. army .