 Only the Second-World-War Japanese 40 cm/45 Type 94 had a larger calibre, , but the British shell was heavier.The gun was a scaled-up version of the BL 15 inch Mk I naval gun and was developed to equip the "large light cruiser" (a form of battlecruiser) .Its barrel length of 60' was 40 just calibers, slightly limiting its muzzle velocity.