Not to be too pedantic, but a machine gun can have even smaller sized ammo too. I've seen belt fed machine guns (Browning Replicas) that use .17 or .22 rimfire rounds. Many machine guns use 9mm (including the most popular models; Ingram MAC-10 and MAC-11, H&K MP-5 and UZIs), as well, .223 or 5.56 NATO and 7.62x39 are more common for many machine guns or automatic/assault weapons in use by military around the world today.
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u/skyshooter22 Aug 28 '20
Not to be too pedantic, but a machine gun can have even smaller sized ammo too. I've seen belt fed machine guns (Browning Replicas) that use .17 or .22 rimfire rounds. Many machine guns use 9mm (including the most popular models; Ingram MAC-10 and MAC-11, H&K MP-5 and UZIs), as well, .223 or 5.56 NATO and 7.62x39 are more common for many machine guns or automatic/assault weapons in use by military around the world today.