FM 23-91 MORTAR GUNNERY - BITS

1 HEADQUARTERS FIELD MANUAL 23-91 DEPARTMENT OF THE ARMY MORTAR GUNNERY DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited PCN 32002341000* fm 23 -91iFIELD MANUALHEADQUARTERSNo. 23-91 DEPARTMENT OF THE ARMYW ashington, DC, 1 March 2000 MORTAR GUNNERYCONTENTSPagePreface .. viPart OneINTRODUCTION AND FUNDAMENTALSOF MORTAR GUNNERYCHAPTER 1. INTRODUCTION1-1. Organization .. 1-11-2. General Doctrine .. 1-11-3. Indirect Fire Team .. 1-21-4. MORTAR Positions .. 1-3 CHAPTER 2. FUNDAMENTALS OF MORTAR GUNNERYS ectionI. Elements of Firing Data and 2-12-1.

2 2-12-2. 2-12-3. Vertical 2-12-4. Distribution of Bursts .. 2-12-5. Interior Ballistics .. 2-22-6. Nature of Propellents and Projectile 2-22-7. Standard Muzzle Velocity .. 2-32-8. Nonstandard Muzzle 2-32-9. Exterior Ballistics .. 2-52-10. Trajectory .. 2-5 SectionII. FIRING 2-72-11. Purpose .. 2-82-12. Unit Corrections .. 2-82-13. Standard Range .. 2-9_____DISTRIBUTION RESTRICTION: Approved for public release; distribution is *This publication supersedes FM 23-91 , 6 December 23-91 PageiiSectionIII. FIRE PLANNING .. 2-102-14. Terminology.

3 2-102-15. Target Considerations .. 2-132-16. Support of Offensive 2-142-17. Support of Defensive Operations .. 2-142-18. Fire Support Coordination Measures .. 2-152-19. Company Fire Support Plan .. 2-162-20. Battalion Fire Support Plan .. 2-18 SectionIV. TARGET ANALYSIS AND 2-192-21. Target Description .. 2-192-22. Registration and Survey Control .. 2-192-23. Size of Attack Area .. 2-202-24. Maximum Rate of Fire .. 2-202-25. Amount and Type of Ammunition .. 2-212-26. Unit Selection .. 2-232-27. Typical Targets and Methods of Attack .. 2-24 Part TwoFIRE DIRECTION CENTERCHAPTER 3. INTRODUCTION3-1. Principles of Fire Direction .. 3-13-2. Organization .. 3-13-3. Personnel 3-2 CHAPTER 4. MAJOR CONCERNS OF THE FIRE DIRECTION CENTER4-1.

4 Types of 4-14-2. Computer's Record .. 4-24-3. Data Sheet .. 4-74-4. Angle 4-104-5. Firing Tables .. 4-124-6. Ballistic Meteorological Message .. Computer MET Message .. The 6400-Mil MET Message .. 4-324-8. Computation of MET Corrections for Large SectorCapability .. 4-324-9. Meteorological (MET) 4-35 CHAPTER 5. CALL FOR FIRE5-1. Introduction .. 5-15-2. Observer 5-15-3. Warning 5-15-4. Target Description .. 5-25-5. Method of Engagement .. 5-35-6. Methods of Fire and Control .. 5-3FM 23-91 Pageiii5-7. Message to Observer .. 5-55-8. Call-For-Fire Format .. 5-55-9. Authentication .. 5-6 Part ThreeMORTAR BALLISTIC COMPUTERCHAPTER 6. INTRODUCTION6-1. Description.

5 6-16-2. Audio 6-76-3. 6-86-4. Memory Storage .. 6-96-5. Error Messages .. 6-9 CHAPTER 7. PREPARATION OF FIRE CONTROL EQUIPMENT7-1. Types of Data 7-17-2. Initialization .. 7-5 CHAPTER 8. TYPES OF MISSIONS8-1. Grid 8-18-2. Shift Mission .. 8-58-3. Polar Mission .. 8-78-4. Technical Fire Control .. 8-98-5. 8-108-6. Traversing Fire .. 8-118-7. Searching or Zone Fire .. 8-198-8. Illumination .. 8-228-9. Coordinated Illumination .. 8-25 CHAPTER 9. SPECIAL PROCEDURES9-1. Registration and Sheaf 9-19-2. Mean Point of Impact Registration .. 9-39-3. Radar 9-59-4. Final Protective Fires .. 9-89-5. Immediate Smoke or Immediate Suppression .. 9-119-6. Quick Smoke.

6 9-129-7. Special Keys and Functions .. 9-16 CHAPTER 10. DIGITAL MESSAGE DEVICE SUPPORTED10-1. Application .. 10-110-2. Communications .. 10-1FM 23-91 PageivPart FourM16 AND M19 PLOTTING BOARDSCHAPTER 11. INTRODUCTION11-1. M16 Plotting Board .. 11-111-2. M19 Plotting Board .. 11-311-3. 11-4 CHAPTER 12. PREPARATION OF FIRE CONTROL EQUIPMENT12-1. Observed Firing Charts .. 12-112-2. Modified-Observed Firing 12-1412-3. Transfer of Targets .. 12-1912-4. Deflection Conversion Table .. 12-2212-5. Grid 12-2412-6. Shift Mission .. 12-2412-7. Polar Mission .. 12-25 CHAPTER 13.

7 TYPES OF MISSIONS13-1. Traversing Fire .. 13-113-2. Searching and Zone 13-813-3. Illumination .. 13-13 CHAPTER 14. SPECIAL CONSIDERATIONS14-1. Registration and Sheaf 14-114-2. Mean Point of Impact Registration .. 14-1214-3. Vertical Interval Correction Factors .. 14-1614-4. Radar 14-1814-5. Final Protective Fires .. 14-20 APPENDIX A. MORTAR TRAINING STRATEGY .. A-1 APPENDIX B. SAFETY PROCEDURES .. B-1 APPENDIX C. FIELD-EXPEDIENT SURVEY TECHNIQUES .. C-1 APPENDIX D. FIRE DIRECTION CENTER CERTIFICATION .. D-1 APPENDIX E. TERRAIN MORTAR POSITIONING .. Index-1FM 23-91vPREFACEThis manual provides guidance for MOS 11C soldiers and their trainers on theemployment of the 60-mm (M224 and M19) mortars , 81-mm (M252 and M29A1) mortars , (M30) MORTAR , and 120-mm (M120) mortars .

8 It discusses the practical applicationsof ballistics and a system combining the principals, techniques, and procedures essential tothe delivery of timely and accurate MORTAR fire. (See fm 23 -90 for information onmechanical training, crew drills, and the characteristics, components, and technical data ofeach MORTAR .)This manual is divided into four parts: Part One discusses the fundamentals of mortargunnery; Part Two summarizes the operational procedures of a fire direction center; PartThree describes the capabilities and use of the MORTAR ballistic computer; and Part Fourdescribes the capabilities and use of the M16/M19 plotting proponent of this publication is US Army Infantry School.

9 Send comments andrecommendations on DA Form 2028 (Recommended Changes to Publications and BlankForms) directly to Commandant, US Army Infantry School, ATTN: ATSH-INB-D (MPO),Fort Benning, GA this publication states otherwise, masculine nouns and pronouns do not referexclusively to 23-911-1 PART ONEINTRODUCTION AND FUNDAMENTALS OFMORTAR GUNNERYCHAPTER 1 INTRODUCTIONThe mission of the MORTAR platoon is to provide close andimmediate indirect fire support for the maneuver battalion are organized as part of a company and battalion. They are either sectionsor platoons in airborne, ranger, air assault, light infantry companies, and cavalrytroops. They are organized as platoons in all tank and infantry mechanizedbattalions.

10 Regardless of the organization to which they belong, mortars have thebattlefield role of providing the maneuver commander with immediate indirectfires. They can fulfill that mission when all of the elements responsible forplacing effective MORTAR fire on the enemy are properly DOCTRINED octrine demands the timely and accurate delivery of indirect fire to meet theneeds of supported units. All members of the indirect fire team must bethoroughly indoctrinated with a sense of urgency. They must strive to reduce, byall possible measures, the time required to execute an effective fire For MORTAR fire to be effective, it must be dense enough and must hit thetarget at the right time with the right projectile and fuze.