Ready ammunition becomes less useful as shells grow beyond what the local crew can handle. A capital-caliber round still needs powered machinery to reach and enter the gun. Keeping extra rounds beside the mounting therefore does not create the quick manual reserve possible with smaller weapons. A direct magazine-and-hoist system is simpler once the ammunition is too heavy to reposition by hand.
Notable Point · 1:30:25-1:30:46
Why very large guns stopped relying on ready ammunition
Capital-caliber shell weight makes a powered route from the magazine more practical than local ready rounds.