Naval Guns are usually classified by Caliber (diameter of the bore), Calibers (length of the barrel described in multiples of the diameter of the bore) and a Model or Reference designation. Some nations include a modification designation to indicate a change from the original design.
For example, the description: USN 16″/50 Mark 7 Mod 0 means that the gun was developed by the Navy of the United States of America, has a bore 16 inches (40.64 cm) in diameter, a barrel length of 16 x 50 inches = 800 inches (20.320 m) long and is the seventh version of the 16 inch gun with no modifications to the original Mark 7 design.
The way barrel length is measured may differ between nations and sometimes gun types. Please see Barrel Length / Bore Length below. Generally speaking, the longer the barrel, the more powerful is the gun.
Part 1 – Weapons and Mountings
Part 2 – Ammunition, Fuzes, Projectiles and Propellants
Part 3 – Miscellaneous Definitions