gunner's gauge scales: scales which provide the weight of a sphere (the shot) from a measurement of its diameter; in gunnery these scales were traditionally provided for iron, lead and stone.
gunner's level: instrument used to set the elevation of a large gun, see article on the gunner's sight and level.
gunner's sight: instrument used to elevate and aim a large gun, see article on the gunner's sight and level.
gunner's sight and level: instrument used to set a large gun to the horizontal, or to elevate and aim it on a target, see article on the gunner's sight and level.