TackleberryMCS
Master
Here are a couple barrels I found.
http://www.whiteoakarmament.com/xcart/product.php?productid=17565
http://www.fulton-armory.com/barrelkrieger20hbarss1x77720threaded.aspx
http://www.whiteoakarmament.com/xcart/product.php?productid=17565
http://www.fulton-armory.com/barrelkrieger20hbarss1x77720threaded.aspx