A quarter-inch caliber increase magnified mount demands

Could Britain have mounted its 4.5-inch or 5.25-inch guns in a system comparable to the US 5-inch/38?

The 4.5-inch gun was the more practical candidate because the 5.25-inch weapon's extra caliber and barrel length added substantial size and weight.

A 4.5-inch system was the more manageable British route. The 5.25-inch weapon was more than a nominal five-inch gun: applying the extra quarter-inch across a 50-caliber barrel added over a foot of length. That increase also raised the gun's weight and the demands placed on its mounting. A small change in the caliber label could therefore produce a much larger engineering problem in the complete weapon system.