Cheap Russian ammo typically has a lacquer coating that gums things up after awhile - if you’re shooting a large volume of rounds and not meticulously cleaning your rifle. AK’s have looser tolerances and their chambers are tapered instead of straight-walled & can usually handle it better, though.
I found this VERY scientific, detailed and comprehensive field study on steel vs brass and various brands at lucky Gunner. Quite definitive. A must read for all.
https://www.luckygunner.com/labs/brass-vs-steel-cased-ammo/