The Korean ammo is not corrosive. I don't believe that any 7.62 ammo was ever made that was corrosive. The 7.62 that I have is in very good condition. What I use it for is on my daily walks. It's for killing coyotes and shooting at rocks from unknown distances and field positions, mostly prone. It's not for going to the "range" and shooting small groups. I do not need match grade ammo for this kind of service.
Regards, Keith