why are so many firearms in WWII 7.62mm? (Or pretty close)

Question

I’m not ignorant of firearms at all, but it strikes me as odd that in the 20th century, most firearms ended up using cartridges that are all more or less similar sized .30 caliber bullets, even pistols, although they tended be less powerful bullets due to smaller casings and less powder

In: 6

Answer 1

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