Upotte!! Nano

A new teacher heads to Seishou Academy, a school known for students skilled in marksmanship, but becomes lost and seeks directions at a summer festival. He meets a girl at a shooting range who demonstrates expert shooting ability. She reveals she is not a student, but an assault rifle named FNC affiliated with the academy. The next day, the teacher arrives at the school and observes students, including FNC, practicing with M16s, realizing the school is unlike any other.