British discussion of an 18-inch weapon was grounded in more than a paper calibre. Britain had already produced an 18-inch naval gun and developed shells for it. Operating the earlier weapon also generated practical knowledge that could feed into a later design. That experience would not make a new gun automatic, but it reduced the number of problems designers had to approach without precedent.
Notable Point · 1:56:53-1:57:22
British 18-inch-gun work gave later designers a head start
Later British interest in very large naval guns could draw on a weapon already built, with shell designs and operating experience available for study.