I been wanting a fast twist slug barrel for my Airforce Condor.. Been watching several different barrel liner manufacturers and green Mountain barrels too... I have a lathe but I really didn't want to turn down a 1.00 plus barrel. I wanted atleast 28 inches... So Chaszel .224 barrel liner at 28 inch long and .386 diameter 12 twist was $68.00 plus shipping... I'm going to sleeve the barrel full length with a 10 mm I'd and 12mm od carbon fiber sleeve....Thread the barrel and get a 3/8-24to 1\2-20 thread adapter.... Then sleeve barrel again with full 1 inch carbon fiber sleeve to barrel bushings and tension.... I'm hoping the 12 twist will work out...I'm wanting 1050 fps with hopefully 45 to 60 grain slugs.. I will hand lap.the barrel liner.... I bought this liner because of the price,length, and twist rate....Will let you now how it works out....