It turned out
non corrosive for me. Lever Arms has a pretty good deal (21 cents per round) for
non-corrosive Chinese surplus here:
http://www.leverarms.com/chinese-mil...62x39-fmj.html
I got a crate to test it out back in December. Did the nail test and it came out non corrosive. But a more definitive test happened two weeks ago. I shot 275 rounds of this stuff on my 858 and waited 96 hours before cleaning it. It is indeed non corrosive.
After seeing these results, I went back to Lever and got more ammo. This time they had a nail test on their counter showing results for the ammo they sell. I guess they read CGN too.
Here's the report I posted in another thread:
While non-corrosive, this ammo did leave, IMO, more than the usual amount fine soot that got everywhere. For lubrication I usually use a heavier, more viscous oil. When the soot is mixed with this oil, it forms a black grease like substance - see image of piston at the base where the spring would go. I don't think this is detrimental to function. It just looks nasty. From now on, I'll only use G96 for lubrication on the CZ 858.
After the 275 round session, the piston face that receives the full direct brunt of gases had a rough surface. I lightly scratched a little bit of that roughness to find out what kind of residue it was made of. It looks like it is made of leftovers from the copper wash. The scratches revealed reddish bright metallic color tone of copper. The opposing side on the gas cylinder didn't show any signs of this metallic copper residue.
Did not do any grouping on paper to test the accuracy, but I can say I was consistently ringing a 9"x9" gong standing offhand at 100m. I did find some cartridges that had some small dents somewhere in the case. I also found some split necks. In spite of these, all fired reliably except for one: there was one case of a failure to feed that was quickly fixed with a forward assist. Later on, as I was reloading the stripper clips I found a cartridge that has a longitudinally bent case. I suspect that the one failure to feed was also due to a longitudinally bent case.
All in all, I'm happy with the results. Please excuse the defective focusing prowess of my camera phone for macro close ups. I also tried to get good pictures of the inside of the barrel, but I was disappointed. Suffice to say that after 96 hours the barrel looked very clean giving out a very slightly dull shine. Now here are the photos of the dirty rifle after 96 hours: