A plaque mounted on this #12 naval gun states that it was made by CPR Munitions Department, Ogden, Alberta. Ogden is now within Calgary, the photographer, Harry Palmer's home town. He recalls that his father worked as a machinist making 12# guns at the CPR Munitions Department in Ogden. He believes that the machine his father worked with was called a "hydratel", a type of milling machine.