Quote:
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Originally Posted by WFGood
The 3 inch 50 caliber Mk 21 (76mm)
The largest weapon carried aboard a US submarine was the 5 inch 25 caliber (MK40) cannon. Housed on a moveable mount, submarines located these weapons abaft of the cigarette deck.
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In this context what does the calibre designation mean?
I thought I read a long time ago that it was the ratio between the bore and the barrel length. But that can't be right as the 3 inch 50 cal would be over 12 feet long.
So what does it mean when the 3 inch gun had a 50 calibre designation?