I've fired about 200 rounds of it out of my Bushmaster 16". I was using USGI mags with green followers (and this rifle has never malf'ed using XM193 or Q3131A ammo in about 2000 rds).
I got about 4-5 malfunctions shooting it. Every time it short-stroked the bolt, ejecting the spent case but failing to strip the next round from the mag, with the bolt coming to rest about halfway forward. I could rack the charging handle with a little effort and it would load the next round just fine. The loads seemed really incosistant - some were resulting in huge muzzle flashes with sparks going everywhere, and a few were resulting in no muzzle flash at all (not suprisingly, every time there was no muzzle flash the bolt short-stroked).
I was just shooting cans, so no idea on the group sizes - it was still minute of can accurate.
It still stinks like Wolf used to, but it doesn't seem to gum up the barrel. When I cleaned the rifle afterwards there was no sign of any lacquer and it cleaned up as easily as it has in the past with other ammo.