The Engineering Design Handbook Series of the Army Materiel Command is a coordinated series of handbooks containing basic information and fundamental data useful in the design and development of Army materiel and systems. The handbooks are authoritative reference books of practical information and quantitative facts helpful in the design and development of Army materiel so that it will meet the tactical and the technical needs of the Armed Forces. This handbook is one of a series on Guns and presents information on the fundamental operating principles and design of muzzle devices. Because of higher priorities assigned in the past to other activities, progress in the design of bore evacuators, noise suppressors, and smoke suppressors was not shared with that of muzzle brakes, blast deflectors, and flash suppressors. Therefore, less design guidance is presented for the first group of three than for the second group. However, effort to improve all muzzle devices continues, and this effort is being augmented by studies on human behavior when exposed to the phenomena created at the gun muzzle.