The US Navy’s USS Zumwalt Main Gun Fired Shells That Cost Up to $1,000,000 Each, and at 10 Rounds a Minute That Is $10,000,000 of Ammunition a Minute

Each US Navy Zumwalt-class warship carried two 155mm AGS guns. These were extremely sophisticated, automated loading guns, with magazines buried below deck, automated ammunition handling, and minimal human intervention.