Why the 4.5-inch gun made a better dual-purpose weapon

How good was the Royal Navy's 4.7-inch gun, and why did the 4.5-inch replace it for dual-purpose work?

The 4.7-inch was useful but too long and heavy for fast high-angle handling; the lighter 4.5-inch was easier to train and elevate.

The Tribal mounting was nominally dual-purpose, but it could not elevate far enough for an effective anti-aircraft role. Barrel length and weight were the core handling problems. The 4.5-inch gun preserved a similar calibre-to-length relationship in a slightly smaller and lighter package. That reduction improved training and elevation speed, showing why mounting dynamics mattered as much as shell calibre.