Funny thing that Prvi ammo, at least in .38 special.
I once bough several boxes of their 158 grain LRN .38 special, and found it horribly dirty and it leaded the barrel of my S&W 642 badly. I'm talking this thing shot out smoke like it was loaded with black powder. I shot it once in an indoor range, and it smoked up the whole thing in short order!!
BUT, just recently I ordered some of their 130 grain FMJ .38 specials. WOW, they were the cheapest FMJ .38 special I could find on the net, and boy are they nice! They shoot VERY clean, are accurate, and seem very consistent. Hopefully they changed some things at Prvi Partisan at least in the .38 special loads, seems they have.