mkII. traded 'slave for it. He was dumping a bunch of rifles he got into. It was a UL 223 in the previous life. The owner rebarreled with a sporter weight shaw. It's a fouling sumbish and nothing was ever done with the magbox, so it has feed issues. I've had it awhile and still haven't done anything with it, except putting it into a sporter stock and chooting it.