Tech. Sgt. Adam Mainwaring, 5th Security Forces Squadron combat arms instructor, explains sight alignment during a M4 carbine class at Minot Air Force Base, N.D., Dec. 8, 2017. Combat arms instructors teach up to three classes a day, with an average of 20 students in each class. (U.S. Air Force photo by Airman 1st Class Jonathan McElderry)