They're still too new and KAC is backlogged in mil orders. I've seen a total of 1 .30 cal QDC on GB and every dealer I talk to pins the wait at 4-6 months best case before you could even start the paper work.
That said, I had the opportunity to run a mag of 308 through a 14.5" and a mag of 300 BLK through a 9.5" and I was laughing afterwards. I don't have any technical data to report back, but I have a few fantastic 30 cal cans that were simply out of their league compared to the QDC/MAMS set up. It's just ridiculously impressive. IMO well worth the wait and the $1500. That wait, however, will likely be 1.5 years. Sorry I can't give you more concrete data points...