On another related note there are some notable inconsistencies with regards to ship designs. It appears impossible, when creating a US heavy or light cruiser in the 1940+ era to equip them with 5" secondaries. The design tool limits you to 4" secondaries. Further there significant differences between the various types of 5" guns - the 5/25 and 5/38 have different ballistics, range and armor penetration. Similar differences apply to the various marks and calibers of 4" guns in different nations. The German and several other countries didn't use 'inches' to describe guns - it was expressed in millimeters. For example the German 6" gun was actually 15cm (5.9 inch) - it may seem trivial but there are real world (or game world) implications in terms of performance, range, etc..