""whoever it was in Syria who was responsible for making this purchase realised that NATO 7.62mm ammunition is useless for Soviet or Russian weapons that fire Soviet or Russian 7.62mm rounds.""

I've no intention of joining this three cornered merry-go-round, but the statement above intrigued me.

Given that I know the Russians and NATO use the same calibre, what is the difference which prevents crossover?

I ask out of genuine curiosity Teribus.

Don T.