I found that the Yugo surplus (I had 1954) worked very well in my M48BO; 300m sights at 300ft was on target, as was Romanian 1975 surplus, except the lighter Romanian stuff (I believe 156gr) had a wider spread and I had many cracked (steel) cases over 70rds fired---I won't buy it again.
But the 2010 Serbian PPU 198gr stuff was junk; smokey, smelly, and the sights had to be set at 600m (low) or 700m (high) to get it on target at 300ft. And expensive to boot. Once I fire
off a couple boxes I have left, I won't buy it again. Funny because the chances are they made the old Yugo military stuff back in the day....
Also, I noticed that the Romanian ammo is slightly shorter, and sometimes had feed issues, whereas the other FMJ ammo didn't. The worst is the 139gr PPU soft-point ammo for feeding---the projectile tip is terrible. Between the Yugo surplus and the new Serbian ammo, the surplus has a sharper projectile.
So has been my experience with the 4 different types of ammo---I dream about cases of surplus ammo on stripper clips like they sell in the States!