Supposedly the Soviets developed the 5.45x39mm in response to our fielding the 5.56mm in Vietnam and it is the standard round in use in Russia today and a few other countries but it didn't even begin to replace the 7.62x39 worldwide. Opinions vary on the cartridge, even within Russia, which still has lots of 7.62x39 rifles on hand. I couldn't comment on the Chinese and the development of their new cartridge but it also hasn't replaced all of their older weapons.
Notice how the Russians have not replaced the 7.62x54r.
Did you know that Stoner and Kalashnikov had met? And that Kalashnikov visited Northern Virginia a few years ago, even going to a gun shop?
And if you ever happen to be in Washington, DC, and go to the Kennedy Center, look around the hall where all the flags are. Somebody's flag even has an AK-47 on it. I've never noticed an M-16 on any flag so far.
Notice how the Russians have not replaced the 7.62x54r.
Did you know that Stoner and Kalashnikov had met? And that Kalashnikov visited Northern Virginia a few years ago, even going to a gun shop?
And if you ever happen to be in Washington, DC, and go to the Kennedy Center, look around the hall where all the flags are. Somebody's flag even has an AK-47 on it. I've never noticed an M-16 on any flag so far.