It looks like Tennesee Valley Manufacuring has oct/round barrel made from pipe, the oct section looks straight, that kind of surprised me, I am sure they would provide any type of barrel one wanted it is just that straight opct section looks realy ...bad,funky I had one and did not like the look over the barrel when sighting, it was OK with a rear sight, seems like most everyone is trying to push the tubing barrels now days. I really think that the vendors/builders should mention the style of barrel they offer, many would probably go to a different barrel if the knew what the tubing barrels looked like.