A British jump to 16.5-inch guns might have provoked a larger American response. Moving from 14 to 16 inches would no longer restore parity, so the United States might have skipped directly to 18-inch weapons and forced another British escalation. The 15-inch Mark I followed a less destabilizing path, and 186 barrels supported several capital-ship classes and monitors. A technically superior weapon can be strategically inferior if it accelerates rivals faster than it strengthens its own fleet.
Notable Point · 45:20-48:55
Why a larger gun could lose the strategic race
The choice of 15-inch guns is presented as deliberate restraint intended to win one competition without forcing America and Italy into an 18-inch reply.