Guns and Super Guns
For army artillery, 155mm calibre seems to be the limit. Is there any reason that 155mm has been standardised all over the world now.....?
In the history, we know that Super Guns have been used. Germans used "Paris Gun" of First WW, with a bore of 210mm and range of 120km.
"The first supergun was the Great Turkish Bombard, used by the troops of Mehmed II to capture Constantinople in 1453. It had a 762 mm bore, and fired 680 kg (1500 lb) stones"
Generally speaking, what is the limit between a traditional gun and a super gun? Is 155mm the limit?
Alongwith super guns, Super Howtizers like "Big Bertha" of 420mm were also used in First World War by Germans.
Navals guns seem to be the largest in use today and in the history with 16 inch and 18 inch calibre guns abroad the warships of Second World War. But these ships of 16inch guns were re-used against Iraq in First Gulf War and were also used in Vietnam war. So they are not totally out of service.
These are the Iowa Class Batteships of USN. See the link for a good firing shot
Iowa class battleship - Wikipedia, the free encyclopedia