Yes, the AT LTD weapon is quite real and so is it's slightly larger brother, the 14.0" bbl Recon Rifle (R2). The company does in fact make the upper receiver available to civilians -- if they currently have a Title II M-16 lower. Understand, the company is not oriented at all on the civilian market, with the sole excpetion of it's TTR-700 tactical takedown rifle and the even newer TTR-50.
The principal client list of Arms Tech LTD is the USG and foreign SOF. I have used a COMPAK-16 for several years in both the progressive gain twist polygonal barrel version and in the earlier cut rifling variants. The reliability is all that the referenced article claims and more. Yes, the combination of the gas trap and the special alloy PGTP barrel makes it all happen. In a recent USG/FMS test in the VA Tidewater area, the weapon went over 24,000 rounds withourt failure and still shot a tad over 1 MOA. XM-8? No thanks.
What I really like, in addition to the reliability and accuracy of this weapon is the retained MV of 2,705 fps with M193. We all know what that translates into. Have yet to find another short-barreled 5.56mm CQB-oreiented weapon that delivers this MV and the attendant fragmentation of the projectile. If there is, let me know; I'd sure love to try it.
I haven't had a chance to live fire the QD-223 suppressor, but it's obvviously quite robust Paulson's article certainly stands on it's own merit. After getting back off of AD in a few weeks I'll be able to play with the suppressor and perhaps post some pics and results. Might need a little help in posting them here.