no, I don't know a whole lot about AR's but they there are some with a stamp that says 5.56X45 and some that say 223 really they pretty much the same round, They"re are some small differences in measurement just like 7.62X51 to 308.
The AK rounds are 7.62X39 (AKM) and 5.45X39 (AK74)
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