I purchased a Ko-Tonics 6.8 barrel back in December of 06. I selected the parts and assembled the rifle myself. My reason for going to 6.8 was based on cost and avaibility of parts, parts selection and the most important, better terminal performance than 5.56. I like the AR platform and wanted a larger caliber cartridge without going to 7.62. Not wanting 7.62 is partly due to the fact that if my wife should need the rifle in a moment of need, 7.62 would over power her.