I got this one off EBAY a short time ago. It was labeled as a "Kempy" barrel, and the owner said it was manufactured in the "States". I found short reference toa Kempy who worked at a store in Illinois called Demon Extreme, but their website seems to be dead. The barrel itself is aluminum, has a bore size of ~ .689 and has dual spiral porting in alternating lenghts at the tip. Any ideas or history on this barrel?