The Gunnery Pocket Book, B.R. 224/45, 1945 was created near the end of WW II and therefore represents the peak of British WW II gunnery. This edition has a few small corrections and updates that were added by hand in 1949 that are reflected in the text.

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Richard Pekelney


Image of the the cover. B.R. 224/45, The Gunnery Pocket Book, 1945

B.R. 224/45


small line separator







A table.
Amendment No. - A.F.O.P. No. - Date of insertion in this copy - Initials
No1 - 75147 - 26-5-49 - MEG Otawa



19th June, 1945.

G. 6450/43.

B.R. 224/45-The Gunnery Pocket Book, 1945, having been approved by My Lords Commissioners of the Admiralty is hereby promulgated for information and guidance.

B.R. 224-The Gunnery Pocket Book, dated 1932 and reprint of 1938, and B.R. 154-The Ammunition Pocket Book, 1935, are hereby superseded and all copies should be disposed of in accordance with the instructions in B.R.1-B.R. Catalogue.

By Command of Their Lordships,

Signature of H.V. Markham

To Flag Officers and Commanding
Officers of H.M.
Ships and Vessels concerned.



List of Abbreviations Used in Gunnery x
Introduction Paras.
Objects of the book-Possibilities of the gunnery career-steps in the gunnery career-advancement-recommendations-training 1
Gunnery in Ships
General-A 6-inch cruiser, "Mauritius" class 20
A "Dido" class cruiser-A typical destroyer 32
The Ship's Company
Part played in fighting the ship 41
Naval Guns
How a gun is fired-Construction of the gun barrel-Rifling-Problem of recoil 45
Breech mechanisms-Summary of safety arrangements-The B.L. mechanism 51
The Q.F. mechanism-Care and cleaning 59
Hand Worked Mountings
Principles of mountings-Pedestal mountings-Central pivot mountings-Cradles-Trunnions-H.A. mountings-Recoil arrangements-Run-out arrangements-Intensifiers-Elevating gear-Training gear-Loading tray 85
The 4.7-inch Q.F. Mark IX** gun on the C.P. Mark XVIII mounting 111
The 4-inch Q.F. Mark XVI* gun on the H.A. Twin Mark XIX mounting 117
Maintenance of mountings 122
Power Worked Mountings
General-Liquid used in hydraulic systems-Pipes and joints-Types of valves-Leathers-Pressure supply-Hydraulic machines 130
6-inch B.L. Mark XXIII gun on Triple Mark XXIII mounting 149
5.25-inch Q.F. Mark I gun on H.A./L.A. Twin Mark II mounting 159
Upkeep of machinery 171

Ammunition Paras.
General-Guns-Explosives 175
Cartridges-Tubes and primers-Ammunition packages-Colouring of ammunition packages-Projectiles-Supply and care of projectiles-Tracers and Igniters-Colouring and marking on projectiles-Fuzes-Fuzing of shell-Gaines 179
Aircraft bombs-safety arrangements-supply and fuzing-markings 212
Small arms ammunition-Rifle grenades-Fireworks supplied for Naval service-Fireworks supplied for use in aircraft-Firework boxes-Line-throwing guns-Line-carrying rockets 216
Magazines and shell rooms-Ammunitioning ship 240
Low Angle Firing
Reasons for a director system-Allowances to be made in director firing for elevation and for training 256
For Elevation.-Dip-Differences in muzzle velocity and temperature of charge at each gun-Tilt-Displacement 260
For Training.-Convergence -Drift 267
Summary of corrections 270
The director sight-the "P" sight-The gun receivers, elevation and training-Firing arrangements 271
Electrical transmission and lining up-step by step-synchronous-magslip, indicator and power 284
Director laying and training-practical working of a director sight 292
Errors in director firing due to roll and pitch of ship-due to roll, firing on the beam-due to roll, firing on the bow 295
Target indication-Obtaining the correct range-Obtaining the correct line of fire-Summary of the fire control problem 297
Admiralty Fire Control Clock 304
Typical modern Fire Control Table 312
The fire control team-Composition of the team-Organization for night action-Standard methods of passing orders-Method of using telephones-Positions of controlling and methods of firing the guns-Gun-layer's control 318

Radar-nature of Radar-uses of Radar-limitations of Radar-Radar operators 349
Optical rangefinders-use of rangefinders 354
Principles of the coincidence rangefinder 356
Focus-magnification or power-taking a range-types of field-astigmatizers-light filters 357
L.A. ranging-halving error-mean adjustment error or coincidence error 363
Inclinometers 371
Maintenance of rangefinders and inclinometers 372
Gunsights-trainer's free sight-Parts of a sight-Types of sights-Corrections required at a sight-Maintenance of gun sights-Telescopes 373
Gunlaying and training-when following director-when using gunsights-point of aim-recognition of targets 395
Firing arrangements-local firing-gunlayer's firing-quarters' firing 400
General principles underlying drill at the gun 401
The gun's crew at a destroyer's gun-composition of crew 403
Action drill-action drill common to all forms of fire-action drill for low angle fire 405
Defence and cruising stations at the gun 408
High Angle Firing
Outline of the control system-the problem-principles of deflection 415
H.A.C.S., fuze prediction 427
Fuze keeping clock, fuze prediction 432
The high angle fire control team 436
Air defence of the ship-barrage firing-A.B.U. firing. T.I.U. 446
Drill at the high angle guns 449
Close Range A.A. Gunnery
Necessity for simple control-Close range guns' crews-Close range guns sights - Eyeshooting and Aircraft recognition -type of attack 455
The Pom-Pom director Mark IV-The 2-pounder Mark VIII gun on Mark VII mounting-The Oerlikon 471

Look-outs and Optical Instruments Paras.
Look-outs-Care of binoculars-How to adjust binoculars-How to use binoculars-Typical look-out organisation-Duties of lookouts-Reporting-Recognition 495
Organisation of a Ship's Company
Degrees of readiness in war-time-Alarm signals-Food and sanitation -Spare gear-Casualties 510
Damage Control
Closing doors-Abandoning compartments-Fire-Prevention of fire in a ship
Magazines-Flooding and spraying-Correcting heel and trim-Counter flooding-Damage control communications-General 525
General Maintenance of the Armament in War
Cold weather-Muzzle covers 545
Notes on Boarding Parties 555
Gunnery Practices
Types of practice firings-Training close range guns' crews-precautions during practice firings-Records and recorders-stop watches-notes for recorders 560
Saluting Guns
Nature and number of guns used-Single ship procedure-Fleet procedure 580
Particulars of Armament and Fittings supplied for Service Boats 196
List of Bugle Calls. 202


1. 4.7 inch Q.F. Mark IX** Gun on C.P. Mark XVIII Mounting 111-6
2. 4 inch Q.F. Mark XVI* Guns on Twin H.A. Mark XIX Mounting 117-21
3. " U," "Hat" and " L " Leathers 139-40
4. Illustrating Angle of Dip 260-1
5. M.V. and Temperature Corrector at Elevation Receiver 262-3
6. Tilt Corrector 264-5
7. Illustrating Displacement 266
8. Illustrating Convergence 267-8
9. Typical Arrangement of D.C.T. Crew 255, 271
9a. Gyro Director Sight, Type H Mark I 255, 271
10. Fig. I Elevation Receiver Type " E.M." Mark I 276-8
Fig. II Training Receiver Type "D" Mark IV 279-80
11. Director Layer's and Gunlayer's Firing Circuits 281-3
12. Range and Deflection Step by Step Receiver, Counterdrum Type 285
13. Fig. I Step by Step Transmission 285-6
Fig. II Synchronous Transmission 287-8
14. Principle of Hunter Mechanism 289
15. Fig. I Indicator Magslip Transmission 290
Fig. II Power Magslip Transmission-Three Element System 291
16. Captain's Sight and Open Face Indicator 24,297
17. Admiralty Fire Control Clock Mark I-Plan of Top 304-11
18. The Measurement of Inclination 305-6
19. Typical Modern Fire Control Table 312-7
20. The Low Angle Fire Control Team 318-28
21. The Principle of Optical Rangefinding 356, 360
22. Figs. I and II Heightfinder Cut 360
23. Halving Error in Rangefinders "Erect Image Field" 368
23A. Halving Error in Rangefinders-Inverted Image Field 368
24. Inclinometer Type S.F.13 371
25. Typical Geared Sight-4.7 inch Mark XVIII Mounting 375
26. Parts of a Gun Sight 380
27. Principles of Deflection 421-4
28. Deflection Screen-H.A.C.S. Mark IV 425-6
29. Typical Range Plot-H.A.C.S. 427-31
30. Fuze Keeping Clock Mark II 432-5
31. The High Angle Fire Control Team 436-45
32. Eyeshooting Sights 460-4
33. Pom-Pom Director Mark IV 471-2
34. 2-pdr. Pom-Pom Mark VII Mounting 473-5
35. 20 mm. Oerlikon Gun 476-91
36. Binoculars Pattern 1900A 496-7
37. Air Lookout (A.L.O.) Position 500

1. Typical Gunnery Layout of a "Mauritius" Class Cruiser 23-31
2. Typical Gunnery Layout of a "Dido" Class Cruiser 32-4
3. Typical Gunnery Layout of a Modern Destroyer 35-9
4. Sections of 6-inch and 4-inch guns 45-9
5. Breech Mechanism 6-inch Mark XXIII gun, open and closed 55-8
6. Typical Q.F. Breech Mechanism with S.A. gear, Diagrammatic Arrangement 59-73
7. Typical Pedestal Mounting 6-inch Mark IX 88
8. Typical Central Pivot Mounting-4.7-inch Mark XVIII 89
9. Typical H.A. Mounting-4-inch Mark IV 93
10. Recoil Cylinder and Run out Springs-6 inch Mark IX Mounting 94-7,101
11. Recoil Cylinder, Recuperator and Intensifier-4.7-inch Mark XVIII Mounting 98-100, 102-3
12. Typical Elevating Gear-4.7-inch Mark XVIII Mounting 104-5
13. Typical Training Gear-4.7-inch Mark XVIII Mounting 108
14. Loading Tray-4.7-inch Mark XVIII Mounting 110
15. Typical Reciprocating Hydraulic Mechanisms 147
16. Methods of carrying pressure into Revolving Structure 142-4
17. General Arrangement of 6-inch Mark XXIII Mounting 149-158
18. General Arrangement of 5.25-inch Mark II Mounting 159-170
19. Colour Markings on Shells 202-3
20. Colour Markings on Bombs 215
21. Markings on Watertight openings 527


This list is not exhaustive. Certain abbreviations have been omitted, e.g., those for the greater part found on packages to which reference should be made in the appropriate handbook, particularly the Handbook on Ammunition.

A. Letter usually denoting foremost centre-line turret or mounting.
(A) Annealed. [ed. Letter A with a full circle around it.]
A.A. Anti-aircraft.
A.A.1 Anti-aircraft rating 1st class.
A.A.2 Anti-aircraft rating 2nd class.
A.A.3 Anti-aircraft rating 3rd class.
A.A.D. Apparatus Air Defence.
A.B.U. Auto Barrage Unit.
A/C Aircraft.
Admy. Admiralty.
A.D.O. Air Defence Officer.
A .D.P. Air Defence Position.
A.F.C.C. Admiralty Fire Control Clock.
A.F.C.T. Admiralty Fire Control Table.
A. F.O. Admiralty Fleet Order.
A/G. Anti Gas.
A.G.O. Air Gunnery Officer.
A.I.C. Action Information Centre.
A .I.N.O. Assistant Inspector of Naval Ordnance.
A.L.O. Air Lookout.
A.M.C. Armed Merchant Cruiser.
Ammn. Ammunition.
A.P. Armour Piercing, Air Ministry Publication.
a.p.v. Average Projectile Velocity.
A.S. Angle of Sight. Admiral Superintendent.
A/S. Anti-Submarine.
A. S.A. Ammunition, Small Arms.
A. S .0. Armament Supply Officer.
Aux. Auxiliary.
A.V.G.I. Auxiliary Vessel Gunnery Instructor.
A.V.G.O. Auxiliary Vessel Gunnery Officer.
B. Letter usually denoting second foremost centre-line turret or mounting.
B.C. Ballistic Cap.
B.D. Between Deck (Gun mountings).
Bg. Bearing.
B.H. Ballistic Height.
B.H.C. Ballistic Height Correction
B.L. Breech Loading.
B.M. Breech Mechanism.
B.P.T. Battle Practice Target.
B.R. Book of Reference.
B.T.U. Bearing Transmission Unit.
C.A.F.O. Confidential Admiralty Fleet Order.
Cal. Calibre.
C.B. Confidential Book.
C.B.R. Confidential Book allowed to Ratings.
C.E. Composition Exploding.
C.G. Captain of Gun.
e.g. Centre of Gravity.
Chg. Charge.
C.N.F. Common Nose Fuzed.
C.O. Control Officer.
C.O.A. Chief Ordnance Artificer.
Comd. Gnr. Commissioned Gunner.
Convtd. Converted.
C.O.O. Commissioned Ordnance Officer.
C.O.S. Change Over Switch.
C.P. Central Pivot. Calculating Position. Common Pointed.
C.P.B.C. Common Pointed Ballistic Capped.
C.P.C. Common Pointed Capped.
C.R. Calibre Radius. Commencement of Rifling. Close Range.
c.r.h. Calibre Radius Head.
C.R.1 Control Rating First Class.
C.R.2 Control Rating Second Class.
C.R.3 Control Rating Third Class.
Ctg. Cartridge.
C.W.P. Wooden Packing Case.
D.A. Direct Action (Delay Action occasionally).
D.a. Deflection in Azimuth.
D.A.I. Direct Action Impact.
D.B. Dive Bombing.

D.C. Damage Control. Depth Charge.
D.C.T. Director Control Tower.
D.E. Director Elevation.
Def. Deflection.
D.E.M.S. Defensively Equipped Merchant Ship.
Det. Detonator.
Dir. Director.
D.1 Lateral Deflection.
D.N.P. Di-Nitro-Phenol.
D.O. Director Officer.
D.T. Director Training.
D.v. Vertical Deflection.
E.A.O. Explosives Accounting Officer.
E.B.I. Enemy Bearing Indicator.
E.M.F. Electro-Mechanical Firing.
Exd. Examined.
Expl. Exploder.
F.A. Fixed Ammunition.
F.C. Fire Control. Full Charge.
F.C.B. Fire Control Box.
F.C.T. Fire Control Table.
F.D.O. Fighter Direction Officer.
F.K.C. Fuze Keeping Clock.
F.O.G.M.O. Fitting Out Gun Mounting Officer.
F.O.G.O. Fitting Out Gunnery Officer.
F.O.B. Forward Observer (Bombardment).
F.O.S. Fall of Shot.
f.s. Feet per Second.
F.T. Field Training.
F.T.P. Follow the Pointer.
Fzd. Fuzed.
G. Followed by a number indicates Gunpowder Grain size.
G.A. Gunnery Aircraft (Radar Set).
G.B. Gunnery Barrage (Radar Set).
G.B.I. Gyro Bearing Indicator.
G.C. Gunnery Close Range (Radar Set).
G.C.O. Gunnery Control Officer.
G.C.T. Gun Control Tower.
G.E. Gun Elevation.
G.I. Gunnery Instructor (R.M.)
G.L. Gunlayer.
G.L.O. Gunnery Liaison Officer.
G.L.W. Gunnery Lieutenant's Writer.
G.M. Gunner's Mate.
Gne. GaMe.
Gnr. Gunner.
Gnr. † Dagger Gunner (Gunner Instructional).
G.O. Gunnery Officer.
G.P. Gunpowder, General Purpose.
G.Q's. General Quarters.
G.R. Gun Range.
G.R.U. Gyro Rate Unit.
G.S. Gunnery Surface (Radar Set).
G.S. General Service.
H.A. High Angle.
H.A.C.P. High Angle Calculating Position.
H.A.C.S. High Angle Control System.
H.A.D.E.S. High Angle Director Eyeshooting Sight.
H.A.D.T. High Angle Director Tower.
H.E. High Explosive.
H.E.S. High Explosive Substitute.
H.G.R. Hitting Gun Range. Higher Gunnery Rating.
H.O. Hostilities Only.
How. Howitzer.
H.S.C.T. Hot Solventless Carbamite Tubular (cordite).
H.V. High Velocity.
Hyd. Hydraulic.
Hyg. Hygrometer.
Ig. Igniter.
Incl. Inclination.
I.N.O. Inspector of Naval Ordnance.
L.A. Low Angle.
L.D.S. Local Director Sight.
L.E. Lee Enfield.
L.G. Lewis Gun. Large Grain (gunpowder).
L.P. Low Power.
L.R.1 Layer Rating First Class.
L.R.2 Layer Rating Second Class.
L.R.3 Layer Rating Third Class.
L.S.T. Line of Sight Training.
M.A.C. Main Armament Control.
Mag. Magazine.
M.C. Modified Cracked (Cordite).
M.D. Modified (Cordite).
M.D.T. Modified Tubular (Cordite).

M.G. Machine Gun.
Mk. Mark.
M.L. Metal Lined. Muzzle Loading.
M.P.I. Mean Point of Impact.
M.T. Temporary local colloquial mark for an emptied package.
Mtg. Mounting.
M.V. Muzzle Velocity.
N. Letter on Armament Stores for Naval Service.
N.A.D. Naval Armament Depot.
N.C. Nitro-Cellulose.
N.C. R. Naval Cordite Regulations.
N.M. & E.R. Naval Magazine and Explosive Regulations.
N.O.I.O. Naval Ordnance Inspecting Officer.
N.R.V. Non-Return Valve.
N.T. Night Tracer.
O. Marking of certain watertight doors (see Chapter 12).
O.A. Ordnance Artificer.
O.A.(O) Ordnance Artificer qualified in Optical Instruments.
O.B.L. Ordnance, Breech Loading.
Oer. Oerlikon.
O.F.I. Open Face Indicator.
O.M. Ordnance Mechanic.
O.O.Q. Officer of Quarters.
O.P. Observation Post (bombardment).
Opr. Operator.
O.Q.F. Ordnance, Quick Firing.
Ord. Lt. Ordnance Lieutenant.
O.U. Official Use (books).
P. Letter signifying Pedestal type mounting.
Followed by a number may indicate a gun, or mounting on the Port side.
On a package may indicate the size of gunpowder (pebble).
P.A. Picric Acid.
P.A.C. Parachute and Cable.
P.C.O. Principal Control Officer.
Pdr. Pounder, as in 2 pdr., 3 pdr.
Perc. Percussion.
P.HD. Priddy's Hard. Note.-Suitable initials or monograms are used for
all Armament Depots. A complete list may be found in Regulations for Naval Armament Services, Part 2, Appendix 1.
Phos. Phosphorus.
P.P. Picric Powder.
P.P.I. Plan Position Indicator.
Prac. Practice.
Proj. Projectile.
P.S. Powder Substitute (practice projectiles).
P.S.G.I. Patrol Service Gunnery Instructor.
P.S.G.L. Patrol Service Gunlayer.
P.S.S.G. Patrol Service Seaman Gunner.
Q Letter usually denoting third centre-line turret where more than four such turrets are fitted.
Q.E. Quadrant Elevation.
Q.F. Quick Firing.
Q.O. Rating Qualified in Ordnance.
Q.R.1. Quarters Rating First Class.
Q.R.2. Quarters Rating Second Class
Q.R.3. Quarters Rating Third Class.
R. Repairable.
R.C.1. Radar Control Rating First Class.
R.C.2. Radar Control Rating Second Class.
R.C.3. Radar Control Rating Third Class.
Rcpr. Recuperator.
Rcvr. Receiver.
R.D. Research Department usually followed by a letter or figure to indicate formulae.
R.D.F. Term superseded by RADAR.
Red. Ch. Reduced Charge.
R/E & D.U. Range to Elevation and Deflection Unit.
REFLD. Refilled.
REPD. Repaired.
R/E.U. Range to Elevation Unit.
R.F. Rangefinder. Rim Fire.
RF/D. Rangefinder Director.
R.G.F. Royal Gun Factory.

R.L. Royal Laboratory.
R.N.C. Letters preceding Naval S.C. Cordite lot numbers.
R.O. Rate Officer.
R.P.C. Remote Power Control.
R/T. Radio Telephony.
R.T.U. Range Transmission Unit.
R.Y.P.A. Roll, Yaw, Pitch, Alteration of course (Instructional Apparatus).
S. Denoting Tube for Strikerless lock.
When followed by a number may indicate a gun or mounting on the starboard side.
S.A. Semi-Automatic. Small Arms.
S.A.P. Semi Armour Piercing.
S.A.S.O. Superintending Armament Supply Officer.
S.C. Solventless Carbamite (Cordite).
S.D.V. Screw Down Valve.
S.G. Seaman Gunner. (Obsolescent term.)
Shrap. Shrapnel.
S.S. Sight Setter. Star Shell.
Sub. Cal. Sub. Calibre.
S.V. Stop Valve.
S.V.G.L. Small Vessel Gunlayer.
T. Tracer.
T & P. Time and Percussion.
T.B.I. Target Bearing Indicator.
T.E. Tangent Elevation.
Temp. Temperature.
T.I.C. Time Interval Compensation.
T.I.O. Target Indication Officer.
T.I.R. Time Interval Receiver. Target Indicating Room.
T.I.U. Target Indication Unit.
T.N.T. Tri-Nitro-Toluene.
T.O.F. Time of Flight.
T.P.I. Target Position Indicator.
T.S. Transmitting Station.
T.S.S. Target Smoke Shell.
U.P. Unrotated Projectile.
U.D. Upper Deck (mountings).
V.A. Vickers Armstrong.
V.S. Vent Sealing.
V.S.G. Variable Speed Gear.
V.S.M. Vickers, Sons and Maxim.
W.A. Warning of Aircraft (Radar Set).
W.B. William Beardmore.
W.C. Warning Combined surface and aircraft (Radar set).
W.O.O. Warrant Ordnance Officer.
W.S. Warning of Surface craft (Radar set).
W.T. Water Tight.
W/T. Wireless Telegraphy.
Wt. Weight
X. Letter usually denoting the turret or mounting on the centre line next before the after one.
Used as a watertight door marking. (See Chapter XII.)
Y. Letter usually denoting the after turret or mounting on the centre line.
Used as a watertight door marking. (See Chapter XII.)
Z Mark indicating Lead Azide Detonator.
Used as a watertight door marking. (See Chapter XII.)

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