Well, because of this:
The AK-74 was designed by А. D. Kryakushin’s group under the design supervision of Mikhail Kalashnikov and is an adaptation of the 7.62×39mm AKM assault rifle and features several important design improvements. These improvements were primarily the result of converting the rifle to the intermediate-calibre high velocity 5.45×39mm cartridge.
https://en.wikipedia.org/wiki/AK-74
Interesting. Only telling what I’ve been told as far as 47 vs 74.
Here’s what I have:
https://en.wikipedia.org/wiki/Saiga_semi-automatic_rifle
-SB