I fired 120rds of the WPA military classic 55gr FMJ ammo a few days ago without any problems whatsoever.
My rifle is somewhat of a frankengun, basically an Oly K3B with re-contoured barrel, H3 buffer, and DIY trigger mod. (lightened hammer, JP yellow springs, and setscrew mod, but no sear polishing)
I can't comment on accuracy, as my skills are inadequate to really be able to test accuracy of a gun/ammo, and I was shooting unsupported with iron sights at 25m at a zombie target, and doing relatively rapid fire, basically just having fun. Fun and practice are what cheap Russian ammo is best for, and that was all I was doing.
It actually seems as or less dirty than the PMC X-Tac ammo I've shot, though I didn't really do a full/detailed cleaning of my rifle afterwards, just the chamber/bore, a wipedown of the receiver&BCG, and re-oiling with a few drops of CLP in critical areas. The WPA ammo did however, make more smoke when fired than the X-Tac.