After crawling through grass and brush toward their target, a sniper team from Headquarters and Headquarters Company, 1-36 Infantry Division, attached to the 3rd Infantry Division, set their sights on their target during a two-week training school where U.S. Soldiers trained Iraqi army special forces at the Al Kindi Iraqi army base in Mosul, Iraq.
If you view a circle from any angle it should still look flush... I think the barrel just has an imperfection in the lower right section. It's slanted, not curved... if it was from the viewing angle, the top right section would look slanted as well.