UNCLASSIFIED AD NUMBER LIMITATION CHANGES

1 UNCLASSIFIED . AD NUMBER . AD838748. LIMITATION CHANGES . TO: Approved for public release; distribution is unlimited. FROM: Distribution authorized to Gov't. agencies and their contractors;. Administrative/Operational Use; MAY 1968. Other requests shall be referred to Army Materiel Command, Alexandria, VA. AUTHORITY. USAMC ltr 22 Jul 1971. THIS PAGE IS UNCLASSIFIED . AM Lp - AMC PAMPHLET. ENGINEERING DESIGN. HANDBOOK. GUNS SERIES. MUZZLE DEVICES. lC. 3 0 SF' 8. ' m -WY SUM * ?V BOT DKTHTIJ. HEADQUARTERS, ARMY MATERIEL COMMAND MAY 1968. REDSTONE SCIENTIFIC INFORMATION CENTER. nun 5 0510 00231346 5. FTEADQUARTERS. UNITED STATES ARMY MATERIEL COMMAND.

2 WASHINGTON, 20315. AMC PAMPHLET 17 May 1968. No. 706-251. ENGINEERING DESIGN HANDBOOK. GUNS SERIES. MUZZLE DEVICES. This pamphlet is published for the information and guidance of all concerned. (AMCRD-R). FOR THE COMMANDER: OFFICIAL : CLARENCE J. LANG. Major General, USA. Chief of Staff Chief. Administrative Office DISTRIBUTION. Special AMCP 706-251. PREFACE. The Engineering Design Handbook Series of the Army Materiel Command is a coordinated series of handbooks containing basic in- formation and fundamental data useful in the design and develop- ment of Army materiel and systems. The handbooks are authorita- tive 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.

3 This handbook is one cf a series on Guns and presents informa- tion 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 suppres- sors, 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.

4 This handbook was prepared by the F'ranklin Institute, Philadel- phia, Pennsylvania, for the Engineering Handbook Office of Duke University, prime contractor to the U. S. Army Research Office- Durham. The handbook was prepared under the technical guidance and coordination of a special committee with representation from the U. S. Army Human Engineering Taboratory, U. S. Army Tank- Automotive Command, Rock Island Arsenal, U. S. Army Weapons Command, and Watervliet Arsenal. Comments and suggestions on this handbook are welcome and should be addressed to U. S. Army Research Office Durham, Box CM, Duke Station, Durham, North Carolina 27706. AMCP 706-251.

5 TABLE OF CONTENTS. Paragraph Page PREFACE i LIST OF ILLUSTRATIONS v LIST OF TABLES Vii LIST OFSYMBOLS , viii CHAPTER 1. INTRODUCTION. 1 1 Purpose 1 1. 1-2 Scope 1 1. 1 3 General Description of Gun Muzzle Devices 1 1. 1 Muzzle Brakes 1 1. 1 History 1 1. 1 Purpose 1 2. 1 Description 1-2. 1 Theory of Operation. 1-2. 1 Advantages 1 3. 1 Disadvantages , 1 3. 1 Current State of the Art 1 3. 1 Types 1-4. 1 Blast Deflectors 1 4. 1 History 1-4. 1 Purpose 1-5. 1 Description 1 5. 1 Theory of Operation 1 5. 1 Advantages 1 5. 1 Disadvantages 1 5. 1 Current State of the Art 1-6. 1 Types 1-6. 1 Flash Suppressors 1 6. 1 History 1-6. 1 Purpose and Description of Types 1 7.

6 1 Theory of Operation 1-7. 1 Advantages and Disadvantzges 1 9. 1 Smoke Suppressors 1 10. 1 History , 1 10. 1 Purpose, Description, and Operation 1 10. 1 Advantages and Disadvantages 1 11. 1 Types 1 11. 1 Noise Suppressors 1 11. 1 Bore Evacuators 1 12. CHAPTER 2. MUZZLE GAS FLOW. 2 1 Muzzle Gas Phenomena 2 1. 2 2 Raising of Dust by a Gun Blast 2 3. 2 3 Mechanics of Muzzle Gas Flow 2-4. 2 4 Muzzle Gas Momentum 2 7. AMCP 706-251. TABLE OF CONTENTS (CQNT.). Pcragraph Page CHAPTER 3. MUZZLE BRAKES. 3 1 Theory of Gun Gas Deflection 3 1. 3 Nozzle Flow 3 1. ^^H Thrust Calculations 3 2. ^^ H Discussion 3-2. 3 Example Problem 3 6. 3 2 Performance Calculations 3 7.

7 3 Impulse 3 7. 3 Efficiency cf a Muzzle Brake 3 9. 3 Discussion 3 9. 3 Example Problem 3 10. Effects on Recoil 3-11. 3 Discussion 3 11. 3 Example Problem 3 12. 3 3 Analysis of Specific Types 3 13. Closed Muzzle Brake 3 13. 3 Discussion 3-13. ^^^^9 Example Prcblem 3 15. Open Muzzle Brake 3 16. 3MH Discussion 3 16. 3 Example Problem 3 19. 3 Free Periphery Muzzle Brake 3 21. 3 Discussion 3-21. Example Problem 3 22. CHAPTER 4. BLAST DEFLECTORS. 4 1 Design Procedure mm 4 2 Overpressure Analysis of the Blast Field 4-4. 4 2J 1 Discussion of Procedure 4MM. 4 Definition and Dimensions of Symbols 4 2. 4 Equations of the Analysis 4 4. ^S^M Digital Computer Routine for Overpressure Analysis 4-6- CHAPTER 5.

8 FLASH SUPPRESSORS. 5 1 Performance Requirements 5 II. 5 1. 1 Computed Temperatures of Muzzle Gas-Air Mixtures fun 5 Digital Computer Routines for Muzzle Gas Temperature 5 5. ^^ 1 Length of Bar-type 5 5. 5 2 Cone-type Suppressor 5 12. 5 3 Digital Computer Routines for Flash Suppressor Configuration 5 13. CHAPTER 6. SMOKE SUPPRESSORS OR ELIMINATORS. 6 1 Suppressor Components 6 1. 6 Diverter Design Procedure 6 1. AMCP 706-251. TABLE CF CONTENTS (CONT.). Paragraph Page Example Problem 6 3. WM. Diverter With Uniformly Distributed Port Area 6 4. 6 Casing Design 6 6. 6 Nter Packing Material 66. CHAPTER 7. BORE EVACUATORS. 7 1 General Design Parameters 7 1.

9 7 2 Fixed Nozzle Design Parameters 7 2. 7 3 Check Valve Design Parameters 7 4. 7 4 Sample Problems 7 7. mO Fixed Nozzle 7 7. 7 Check Valve 7-8. CHAPTER 8. NOISE SUPPRESSORS. 8 II General Requirements 8 1. a 2 Sound Suppressor Experiments 8 1. CHAPTER 9. HUMAN FACTORS. 9 1 Introduction 9 1. 9 2 Effects of Blast and Overpressure 9 1. 9 Physiological Effects 9 3. 9 Tolerance Timits 9 5. ABPENDIXES. A 1 Isobar Source Program Tisting A 1. A 2 FlowChart JVIuzzle Gas Temperatures A 4. A 3 Muzzle Temperature Source Program Tisting A . A 4 Flow Chart -Flash Suppressor Design A 6. A Flash Source Program Tisting A 7. A 6 Patents on Silencers A 9. GTOSSARY G 1.

10 REFERENCES R 1/R 2. BIBTIOGRAPHY B^. INDEX I 1. AMCP 706-251. LIST CF ILLUSTRATIONS. Fig. No. Title Page 1 1 Schematic of Closed Muzzle Brake 1- 1 2 Schematic of Open Muzzle Brake 1- 1^ Cone Flash Hider 1 7. 1 4 Bar Flash Suppressor 1 8. 1 S Unsuppressed Flash 1 9. 1 6 Effects of Flash Suppressor 1 9. 1_7 Example of Flash Suppression 1 9. 1 8 Flash Prediction Temperature Curves 1 10. 2 1 Maximum Volume Stage of Shock Bottle 2 f! 2 2 Primary and Intermediate Flash 2 3. 2 3 Three Types of Flash 2 4. 2 4 Development of Muzzle Glow 2 4. 2 5 Steady-state Shape of Shock Bottle 2 5. 3 1 Muzzle Brake Gas Flow Diagram 3- 1. 3-2 Speed-up Factor vs Divergence 3 3.