Just came back from blasting away with the WK to test functionality...its awesome!
I fed it Norinco 5.56, and some reloads i had from a few years ago that are on the mild side. Primary concern was popping primers and tight chamber.
So far no issues. It fed from all my mags issue free other than the IMI beowulf mags but thats because the back rib where the follower rides up is too narrow and the mag trips the bolt hold open.
Its awesome...im giddy with it...other than the craptastic trigger, this thing is awesome...soft shooting, LIGHT, its almost as light as my SU16.