Comments by "" (@neutronalchemist3241) on "OTO Melara 76mm Cannon | ITALIAN NAVAL FIREPOWER" video.

It's actually war propaganda bullshit, disproved by pictures of the salvos and by the reports of actual hits in battles. Despite generally using hig velocity shells, that tend to have greater horizontal dispersion for purely geometrical reasons, the Italians generally managed to keep the longitudinal dispersion below 2%, that was considered good by any navy at the time. Italian cruisers scored several +20km hits during WWII. The longest hits by cruisers of every nation involved.
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OTO-Melara is one of the most succesful manufacturer of naval artillery in the world.
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OTO Melara produces 127mm naval guns too. 70mm is the smallest gun effective vs. ships (otherwise the holes are two small to sink it), 130mm is the biggest gun effective vs. aerial targets (otherwise the ROF is too slow to hope to intercept them) that's why all the modern ships tend to have guns in this interval. Guns in the 70mm range are often preferred because their installation occupies only a deck below the gun itself (and there are installations completely over the deck even if with a limited amounts of rounds), so they are very flexible. 120mm guns requires two decks below the gun, so their installation has more constraints.
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Yes. Plenty of water in the sea, so no need for a closed system.
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Tests shown that 76mm is the minimum required to reliably sink even a merchant ship in a reasonable time. That's why most modern naval guns go form 76mm to 120mm (the maximum that can be used in anti-air role, before the ROF becoming too slow for that).
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Because: 1) modern day ships are not armoured, and a 76mm automatic gun can sink them 2) 76mm fires fast enough to be used in anti-air role (especially the Oto Melara, with guided ammunitions). 3) Actually this gun can be used against modern MBTs, see "Vulcano" guided ammunitions. Since the projectiles are coming from above, the tank is practically unprotected against them.
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