Why a 300-round-per-minute six-inch gun is impractical

Could an autoloader fire six-inch shells at roughly 250 to 300 rounds per minute?

No current system can do so, and handling six-inch ammunition at that rate would impose extreme demands on any autoloader.

No current loading system can deliver roughly 250 to 300 six-inch rounds per minute. Ammunition of that size would place extreme demands on an autoloader at the proposed rate. A system could be developed for the calibre, but nothing supports a figure close to the one in the question. The unsuccessful attempt to adapt the British Army's AS90 gun for shipboard use shows why a land weapon is not an easy naval fit. Rate of fire must remain compatible with ammunition size and dependable operation at sea.