American Projectiles and Explosives - 20mm and 40mm Projectiles

American Projectiles and Explosives

Minor Caliber Projectiles




20mm Ammunition

Two types of 20mm weapons are at present in service use in the Navy: the Oerlikon anti-aircraft gun and the Hispano-Suiza aircraft gun.  These types differ widely in construction and functioning; and it is emphasized that the ammunition, though somewhat similar in external appearance, is not interchangeable.




Ammunition for Oerlikon Gun

The Oerlikon gun and its ammunition are of naval manufacture and design.  The ammunition may be distinguished from that designed for the Hispano-Suize gun by the reduced diameter of the extractor lip at the base of the cartridge case.  For identification of the individual types of rounds, the body of the projectile is painted a distinctive color, as follows:

*When the projectile is assembled with "Dark Ignition" tracers, a 1/8-inch bright red band will be painted around it midway between the bourrelet and the rotating band.

The Mark and Mod, manufacturer's initials or symbol, and lot number are stamped around the body of the projectile.


Abbreviations in Minor Calibers

H.E. --- High Explosive
I. --- Incendiary
T. --- Tracer
B.L. --- Blind Loaded
P. --- Plugged
S.D. --- Self-Destructive
D.I. --- Dark Ignition



Ammunition for Hispano-Suiza Gun

This gun and its ammunition are Army-designed but have been adopted as Naval equipment with the installation of the gun on Naval planes.  The ammunition is distinguished from that designed for the Oerlikon gun by the extractor lip on the base of the cartridge, which is the same diameter as the rest of the case.  Two series of ammunition for this gun are in use.  The "Old Series" consists of unmatched rounds, some adapter from British prototype, others designed by the Army.  The "New Series" is a set of ballistically matched rounds designed by the Army to supersede those of the "Old Series".  For identification of the individual types of rounds, the body of the projectile is painted a distinctive color, as follows:

1.1"/75 Ammunition

The body of these projectiles, now obsolete items, were unpainted except for two dots below the fuze, indicating as follows:

Explosive D --- Yellow dot
Tracer --- Red dot

A newer color marking was proposed for the 1.1-inch ammunition.  Some projectiles may be found painted as follows:

H.E.-T.  -- Light Gray with White band
H.E.-T./S.D. -- Dark Green with White band
B.L. and P. -- Red overall
B.L. and T. -- Red overall with White band




40mm Ammunition

These projectiles are identified by distinctively colored bodies, as follows:

The tracer composition is either a red burning mixture in the tracer -- "T" rounds -- or a non-luminous burning compound in the "Self-Destructive" rounds.

"Dark" and "Dark Ignition Tracer": To eliminate the blinding effect on 40mm and 20mm gunners from tracer fire at night, and also to make the origin of tracer fire less distinct, these tracers were developed toward the close of the war.  The dark ignition tracer is invisible until the projectile is 100 to 400 yards from the gun's muzzle, and then it is visible for the rest of its time of flight.  Details of these tracers are described with their appropriate projectile and tracer housing.

Inert Fillers

(For details on explosive payloads, please see earlier updates in the US explosive updates)


Blind Loaded and Plugged (B.L. & P.):  A projectile may be loaded with sand or other inert material and sealed with a solid base plug, or the tracer hole (fuze hole) in a base plug may be blanked off.

Blind Loaded and Tracer (B.L. & T.): These projectiles have an inert load, but a tracer is inserted in the fuze hole of the base plug.

White Phosphorus: An unstable smoke-incendiary agent, white phosphorus ignites when exposed to air and produces dense white smoke.  It also has its incendiary, anti-personnel effect.

Gas: The various types of gas fillings are listed further below.

Color and Markings of new projectiles, 3-inch and larger

Explosive Indicator

Yellow ---- Explosive D
Grey ---- Black Powder
Green ---- TNT
1/2 Grey and 1/2 Green band ---- TNT and Black Powder mix
Red ---- Inert material or empty
Blue ---- Composition A

Time Fuze Stripe

Projectiles having a nose time fuze shall have a 1/4-inch white stripe painted longitudinally from the stationary lug on the fuze two inches aft.

Body Color

Black ---- AP

Slate Grey ---- Common

Green -- AA, HC, and AA Common

Light blue with two white stars ---- Illumination

Aluminum ---- Window

White ---- Shrapnel

Ocean Grey ---- Smoke, Gas, or Incendiary

Red ---- Targer ammunition

V.T. Fuzed

The letters "V.T." 3/4-inch high are stencilled just before the rear edge of the paint indicating the burster charge.

Tracer Band

A white band with four dots 90 degrees apart indicates the color of the tracer.

Spotting Band

The color indicates the color of the spotting charge.

"Window" Mark

This consists of a one-inch high "W" on each side, 180 degrees apart, just abaft the forward bourrelet.

Stenciling on Body

The following information is stenciled between the rotating band and the forward bourrelet on new projectiles:

-Ammunition lot number

-Caliber and type of projectile

-Mark and Mod of projectile

-Type nose fuze (whether MTF, PDF, VTF, Mk 32 and similar types, or Dummy Nose Plug)

-Mark and Mod of fuze

-Lot number of fuze (for Mk 32 and similar types only)

-Mark and Mod of auxiliary detonating fuze

-Mark and Mod of base detonating fuze

-Mark and Mod of tracer 

-Color of tracer

-Mark and Mod of guns in which projectile can be used

-Mark and Mod of "Window" load

-Stamped on rotating band

-Mark and Mod of projectile

-Size and Type of projectile

-Lot number and year of specification

-Inspector's seal and initials

-Sometimes the manufacturer's name is included here

Stamped on base or on base plug

-Mark and Mod, size, and type of projectile

-Lot number, year of specification

-Inspector's seal and initial

-Manufacturer's name

The serial number of the projectile will also be stamped on the base plug on the side of the body, and on the windshield if present.

Chemical Filler Markings

Two green bands, 1/2-inch apart ---- Persistent casualty gas
One green band ---- Non-persistent casualty gas
One red band ---- Harassing gas
One yellow band ---- Smoke
One purple band ---- Incendiary

Also, on projectiles having a chemical filler, there is stenciled the type of chemical, such as SMOKE, INCENDIARY, or GAS, and the symbol or letter designating the particular filler.





Color and Marking of older projectiles, 3-inch and larger


In addition to the explosive filler, body color, spotting specifications, and base and band stamping mentioned above, the older projectiles had the following markings:

Tracer Band: White band with three dots, indicating tracer color, 120 degrees apart.

V.T. Fuzing: One-half inch red band painted one-half inch abaft the nose fuze.


Stenciled on the body

-Size, caliber, Mark and Mod of projectile
-Mark and Mod of fuzes
-Explosive filling and density of loading
-Abbreviated name of loading dept.
-Initials of Chief Inspector
-Date of filling and marking; any changes in filling, fuzing, etc.


Stamped on base

Weights before and after filling.

Next Time: 3-inch Projectiles

American Projectiles and Explosives - High Explosives Inventory and Nomenclature (Part 1)

American Projectiles and Explosives





Introduction to American High Explosives


The information that will follow in the following weeks and months is, like with other inventories, taken from documents written at the time or soon after World War II.  These were written by British or American teams in order to categorize enemy or friendly ordnance.  This American inventory should be up to date to about February 1946, and was published in 1947.

Status

Ordnance included was that classified as service, together with some obsolete, obsolescent, and experimental types.  The experimental items were those being actively developed in the Spring of 1946, with the probability that they would soon be standardized.

Obsolete and obsolescent equipment described was that which might still be in existence in depots or dumps at the time of writing.

Nomenclature

When a Navy ordnance item is approved for testing, it is assigned its Mark number.  It retains this Mark number whether finally approved for service use or rejected.  Modifications to the original Mark design are treated likewise.  Army items under development as assigned "T" numbers.  If the item is standardized by the Army's Ordnance Technical Committee, the "T" designation is dropped and an "M" number is assigned.

When a modification on a "T" item is made, the change is given an "E" number: for instance, "T1E1".  If the modification is adopted as a standard item, the modification gets an "A" number in sequence of change on the standard item: for instance, "M66A1, M66A2".  The Army's Chemical Warfare Service uses "E" and "R" designations for experimental items instead of the "T" and "E" numbers, respectively, of the Ordnance Department.

For aircraft ordnance there are items which are standardized for both the Navy and the Army.  These are given the letters "AN" before their original standard name; thus, AN-Mk 33 or AN-M63A2.

Prior to June 1925, the Army's nomenclature for bombs was by a Mark and a Roman numeral, like the early Naval Mark designations, but the modifications were distinguished by the letter "M" and another Roman number (Mk I M II) where the Navy used the abbreviation "Mod", (Mk 1 Mod 2).  In 1925, the Army adopted the "M" system.  The Army-Navy Standardization Board was created in June, 1941.

American High Explosives


Two scales are employed to compare sensitivity of explosives.  The first of these is the "Laborator Impact Sensitivity" in which the ratio of the drop of a given weight necessary to detonate the explosive under discussion to the drop necessary to detonate TNT, is expressed on a percentage basis.  TNT will be given as 100.

The second is a scale of "Bullet Impact Sensitivity" with RDX rated at 0 and TNT at 100.  The other explosives are expressed in relation to these two.  Velocity of detonation varies directly with the density to which the explosive is cast or pressed, all other factors being constant.  The velocity of detonation will, therefore, be given for a definite density of loading.


TNT (Trinitrotoluol)

TNT is powerful, brisant, easy to load by casting since its melting point (Grade A) is 80.2 degrees Celsius, stable under all stowage conditions, insensitive enough to stand all normal handling, and even capable of standing bullet impact when cast.  The Navy uses it as a booster in a pressed granular form in which it is more sensitive to detonator action.

The velocity of detonation is 22,300 feet/second at a density of 1.55.  Its Laboratory Impact Value is 100.  Its Bullet Impact Value is 100.  Its color is yellow to buff.



Tetryl (Trinitrophenylmethylnitramine)

Tetryl, because of its combination of high power, brisance, and sensitivity, is the standard US booster charge, although the Navy still uses an appreciable amount of granular TNT.  It has been tried for main charge loads in small caliber projectiles, but has proved too sensitive to withstand the setback in all but 20mm.  It is used as abase charge in compound detonators.  This, in effect, makes it  a small booster in intimate contact with the initiating explosive.

The melting point of Tetryl (130 degrees Celsius) is too high to allow it to be melted and cast.  It is loaded by being mixed with small quantities of graphite or stearic acid which serve to lubricate it while it is being pressed into pellets.  Tetryl is quite safe to handle and is extremely stable in stowage.  Exposed or loose Tetryl should not be handled, as it may cause dermatitis.

The velocity of detonation is 24,400 feet/second at a density of 1.55.  Its color is light yellow, but it is usually gray because of the graphite.  It is more powerful than TNT.  Its Laboratory Impact Value is 45, and its Ballistic Impact Value is 61.



Explosive D (Ammonium Picrate)

Explosive D is the standard main charge for armor-piercing bombs and projectiles and other Navy projectiles.  While its power and brisance are slightly inferior to TNT, it is much more insensitive to shock and will stand impact on armor plate without being deflagrated.  It has two other disadvantages: (1) Its melting point is too high for it to be melted and cast, and it is therefore loaded by being pressed into cases by a hydraulic ram; (2) It reacts with metals to form extremely sensitive compounds.  This is counteracted by covering the interior of bombs or projectiles with acid-proof lacquer.

Its rate of detonation is 21,300 feet/second at a density of 1.48.  Its power and brisance are about 95% those of TNT.  Its Laboratory Impact Value is 99; its Bullet Impact Value is over 100.  Its color is yellow or yellow-orange.

RDX (Cyclonite Cyclotrimethylenetrinitramine)

RDX is the most powerful and brisant of the military high explosives, and it is considered much too sensitive to use alone.  It seems to be about half way between Tetryl and PETN in mixtures of other explosives and inerts which reduce the sensitivity to a safe range, while the mixtures have a very high brisance and power due to the RDX.  It has excellent stowage qualities, but, because of its sensitivity, it is shipped immersed in water like an initiating explosive.

The velocity of detonation is 28,000 feet/second at a density of 1.70.  Its Laboratory Impact Value is 34.  Its Bullet Impact Value is 0.  Its color is white.



PETN (Pentaerythritetetranitrate)

PETN resembles RDX in its characteristics.  It is somewhat more sensitive, but almost equal in power and brisance.  It is appreciably more sensitive to percussion and impact than Tetryl and is, therefore, not used alone as a booster, though it is being used as a base charge in some compound detonators in the way Tetryl is.  The tendency of PETN to burn is much less than that of similar explosives.   Its main use alone in the service is in primacord.  When use alone, PETN is combined with a small quantity of wax to desensitize and lubricate it, and is loaded by pressing.  It is important to know that PETN in primacord is very insensitive to flame, shock, and friction, and therefore must be detonated by a cap.

The velocity of detonation of PETN is 26,000 feet/second.  The velocity of detonation of primacord is 20,500 feet/second.  Its Laboratory Impact Value is 22.  Its Bullet Impact Value, though, not given, would be about equal to RDX (0).  Its color is white.



Haleite (EDNA, Ethylenedinitramine)

Haleite is a new explosive that probably will not be used alone, but will be used in combination with other explosives.  It is somewhat more powerful than TNT.  Its sensitivity is about the same as Tetryl.  It melts at 180 degrees Celsius, but one report states that it may detonator in the manner of an initiating explosive at that temperature or a little lower.  If loaded alone, it would be pressed.

Its velocity of detonation is 25,000 feet/second at a density of 1.5.  Its Laboratory Impact Value is 46.  Its Bullet Impact Value is not available.



Nitroguanadine

Nitroguanidine is the explosive incorporated in the Navy's new double-based propellant powder, SPCG.  It is unusual in being a high explosive that is so cool in its reaction that it explodes without flash.  It is comparable in strength to TNT, and its sensitivity is of the same order.

Its rate of detonation is 24,400 feet/second at a density of 1.50.

Amatol

Amatol, a substitute for TNT, is a mixture of ammonium nitrate and TNT; the percentage of ammonium nitrate, depending on the availability of TNT, has varied from 40% to 80%.  Its power and brisance decrease with the increasing percentages of nitrate, and its sensitivity decreases at the same time.  However, it is still fairly good high explosive, even when the TNT is reduced to 20%.  80/20 cannot be cast, since it is not fluid enough to pour even when TNT is molted, and it therefore must be loaded by extrusion.  Amatol has a disadvantage in that it is very hygroscopic and therefore is usually protected by a sealing pour of pure TNT.

The velocite of detonation of 50/50 is 19,700 feet/second at a density of 1.54.  Its Laboratory Impact Value is 93.  Its Bullet Impact Value is about 100.  Its color is buff.

Composition B

Composition B is intended to be used a s a more powerful replacement for TNT in the loading of some of the large size G.P. bombs, and in fragmentation bombs.  It will be used where an explosive with more power and brisance is of tactical advantage and there is no objection to a slight increase of sensitivity.

Composition B1 is a mixture of 59% RDX, 40% TNT, and 1% wax.  Composition B2 is a mixture of 60% RDX, 40% TNT.  The TNT cuts down the sensitivity of the RDX to a safe range and lowers the melting point to 81 degrees Celsius, allowing the material to be cast-loaded.

Composition B might be detonated at low order by bullet impact, but it is almost as insensitive as TNT in this respect .  It has an extremely high shaped-charge efficiency.

Its velocity of detonation is 24,500 feet/second at a density of 1.6.  Its total energy of blast in air is about 116% of that of TNT.  Its Laboratory Impact Value is 79.  Its Bullet Impact Value is 79.  Its color is yellow to brown.

Torpex

Torpex is one of the explosives developed during this war to be used mainly in underwater ordnance.  The original Torpex (Torpex 1) was a mixture of 45% RDX, 37% TNT, 18% Aluminum powder (1% wax added).  It is used in mines, torpedo warheads, and depth bombs.  Torpex is more sensitive than TNT; its bullet impact and drop test sensitivities are of the same order as those of Tetryl.  It is quite stable in stowage, though it produces gas, causing pressure in the case.  It is insensitive enough to stand all normal handling.  Its melting point is low enough for it to be cast-loaded.

Its velocity of detonation is 24,000 feet/second at a density of 1.72.  It is 141% as powerful as TNT.  Its Laboratory Impact Value is 53.  Its Bullet Impact Value is 48.  Its color is slate gray.

DBX (Depth Bomb Explosive)

DBX is another aluminized RDX mixture, and its name suggests its intended use.  It is 21% RDX, 21% Aluminum Nitrate, 40% TNT, 18% Aluminum.  It was designed to replace Torpex, which is closely resembles in sensitivity, strength, brisance, and energy of shock in water, but half of the strategic RDX in Torpex is replaced by Ammonium Nitrate in DBX.  It will probably not be used, as the present supply of RDX seems adequate to meet the demand.  DBX can be cast, though its melting range of 98-105 degrees Celsius is about the upper limit.

Its velocity of detonation is 22,300 feet/second at a density of 1.68.  It is 143% as powerful as TNT under water.  Its Laboratory Impact Value is not given.  Its Bullet Impact Value is 51.  Its color is gray.

Next Time: High Explosives Inventory (Part 2)

German Projectiles - Introduction and Colour and Markings System

German Projectiles





Introduction to German Artillery Projectiles



Classes of German Artillery Ammunition

Class #1: (Fixed Ammunition) Ammunition, the complete round of which, can be loaded into the weapon in one operation.  The cartridge case, containing a primer and propelling charge is permanently crimped to the projectile.


Class #2: Ammunition, the complete round of which, is loaded in two operations.  The cartridge case, containing a primer and a propellant charge is not crimped to the projectile.  The propelling charge is in bags and the charge can be varied at the point of firing.  The projectile is packed and shipped separately, and the cartridge case and propellant are packed as one unit.


The Germans employ cartridge cases in all their artillery ammunition.  The cases are employed for the main purpose of preventing the escape of gas to the rear.

 Nomenclature

The Germans designate a round of artillery ammunition by the Caliber, Type of Ammunition, (Model No. of the round), Type of Weapon fired from, and (Model No. of the Weapon.)

The caliber of German Artillery Ammunition is measured in centimeters.  The Germans refer to calibers approximately; for instance, the 10.5cm gun is always known as the "s 10cm K.18", (Heavy 10cm Model No.18)

In naming the various types of projectiles, the Germans employ the word, "Granate", (abbreviated "gr." or "Gr.").  "Granate" is used as a base word for all the various types of rounds.  By adding a prefix and/or a suffix to the word, the exact nature of the projectile is indicated.



Prefix added to the word "Granate"

(In order to differentiate between the various types of Armor Piercing Rounds, numbers are added after the word Pzgr.)

Panzergranate 39 -- Pzgr. 39 -- APCBCHE (Armor Piercing Cap, Ballistic Cap [windshield] High Explosive)

Panzergranate 40 -- Pzgr. 40 -- A.P. Shot with a tungsten carbide core

Panzergranate 41 -- Pzgr. 41 -- A.P. Shot with a tungsten carbide core for tapered bore gun (Gerlich gun)

Sprenggranate 41 -- Sprgr. 41 -- H.E. Shell for a tapered bore gun



Suffix added after "Granate"

For the most part the Germans do not give Model Numbers to their artillery ammunition.  In several of the old rounds Model Numbers are indicated.  The numbers used are the lat two of the year in which the round was made standard.  These are only used in the nomenclature when there is more than one model of any specific type.  In the case of the "Pzgr." (Armor Piercing) rounds,  the numbers appearing after the word merely indicates the type of Armor Piercing round and are not Model Numbers.


Rot. or L'spur. (Leuchtspur) included int he designation indicates tracer.

This nomenclature is followed by the word "Patronen" abbreviated Patr., meaning cartridge.  This is the German way of indicating a complete round.  It is similar to the British nomenclature, in that the British use the word "cartridge" to designate all their complete rounds.

The Germans include the name of the type of the weapon in designating their ammunition.  This nomenclature is given in the form of an abbreviation.

 
In some instances a letter in parenthesis is added to the nomenclature after the word indicating the type of projectile.  These letters are used to indicate material of foreign origin.  The following are some of the letters used for this purpose.

(t) Czech
(f) French
(p) Polish
(r) Russian
(o) Austrian

In some cases the following may be included in the nomenclature:

German --- English
              NA --- New Pattern
        umg --- Modified
     St --- Steel


The following details of stencilling on projectiles are arranged in the sequence in which the markings are normally found commencing at the nose of the projectile.

Z.F.Hbgr - (In black) On the windshield of an H.E.B.C. shell indicates the use of a nose fuze under the windshield

R or Mr - (In black near the tip) Indicates the presence of a smoke box.

Arabic numerals - (In black on the head of the shell just below the fuze hole, or on the body of the shell), indicates the type of H.E. filler.  The more common of these are given below.

The following are some examples of German ammunition nomenclature.

4.7cm Sprgr. Patr. Pak (t) - 47mm H.E. Shell for the A.T. gun of Czech make.

3.7cm Pzgr. Patr. 40 Pak - 37mm A.P. Shot - Tungsten Carbide core for the A.T. gun.

7.62cm Pzgr. Patr. 40 Pak. 36 (r) - 76.2mm (3") A.P. Shot - Tungsten Carbide core for the A.T. gun 36 (Russian design).

8.8cm Sprgr. Patr. Flak 36 - 88mm H.E. Shell for the Anti-Aircraft gun 36.




Color of the Projectile

 
Projectiles of the latter type are sometimes painted white.  This color appears to be used for projectiles in the experimental stage supplied for trial by the Army in the field.

Band marking is not common use except for a red band above the rotating band in some shells, indicating a tracer, and a yellow band for the 3.7cm aluminum colored H.E. tracer shell.

The place and date of the filling of the projectile, followed by a lot number in black, is on the shoulder of the projectile in the form of an abbreviation.

The Weight Zone of the projectile is indicated by Roman numerals, black in color near the bourrelet.

In the following instances the type of shell, and to some extend the nature of the filling, is indicated by 2.4" letters stencilled at two positions round the shell midway between the rotating band and bourrelet.

The place and date of assembly, followed by a lot number, are stencilled in 4" black or red lettering above the rotating band, e.g., "Lr 4.640L."



Stamping on the Projectile

The following are stamped on the ogive in the order in which they appear.

1.  Acceptace test number
2.  Delivery number, firm and year of manufacture
3.  Firm's proof mark


The following appear on the body of the projectile:

1. An acceptance stamp, water pressure test and an acceptance stamp, second test.
2. Acceptance stamp (Hardness).
3. Shell model number.
4. Delivery number, firm, year of manufacture, acceptance stamp of release.


The following appear on the base:
1. Delivery number, firm, year of manufacture.
2. Projectile model number.
3. Acceptance stamp for fitted base.
4. Acceptance stamp.




Identification of the Fixed Cartridge Case and Charges

  

  
Stencilling on side of Case


The following details are arranged in the sequence in which the markings are normally found between the approximate center of the case and flange at the base;

1. The caliber, types and model numbers of the weapons for which the round is suitable are stencilled in the form: 7.5cm KWK 40 (7.5cm, tank gun Model 40).  Where a round is suitable for more than one equipment, the designation of the equipment is stencilled in sequence with the letter "u" signifying "and" as a conjunction.

2. The weight of the propellant charge in grams is stencilled int he form of numerals, followed by the letter "g" below the nomenclature of the ammunition. (e.g. "164g")

3. The nature, shape and size of the propellant charge are stencilled below the marking indicating the charge weight.

The following markings are used to indicate the nature of the propellant

  [Note: My copy is either missing #4 and #5, or they don't exist.]

6.  The red stencilling used to indicate propellant charges of a reduced weight for hot climates may be found near the base of the case, just above the flange, or higher up the side of the case, above the other stencilling.  The marking used:  Tp ---- 25* C.  indicates that the normal or standard charge temperature on which the weight of the charge is based is 25 degrees Celsius (77 degrees Fahrenheit).  The German standard charge temperature for normal European temperatures is 10 degrees Celsius. (50 degrees Fahrenheit)

 7. In some instances cases are stencilled:  "Abgebr Ldg" in red.  This marking is found near the base (corresponding to the position of the Tp - 25* C. marking) and probably refers to the propellant charges of low stability which are to be give priority in expenditure.


Stencilling on the base of Fixed Cartridge Cases


Type of the projectile is stencilled in white or black to the left above the primer hole.

In some instances the Roman numerals indicating the weight classification of the projectile are stencilled in white to the right below the primer hole.


Stampings on the base of Fixed Cartridge Cases


Model number of case.
St. - after model number of case -- indicates a steel case.
Model, Cal. and type of weapon.
Manufacturer's Initial.
Delivery number.
Year of manufacture.


Markings on Cartridge Bags in Fixed Rounds


The markings are the same as those stencilled on the side of the case except that the caliber, type and model number of the equipment are not included.

Markings on Semi-Fixed Cartridge Cases


A cardboard or leatherboard cup is used to close the mouth of the cartridge case in a round where the cartridge case is packed separately.

A label, found on the closing cup, contains information corresponding to the stencilling on the side of the fixed cartridge case.  The information is as follows:

Details of the weapon.
Charge weight.
Kind.
Type (size and shape of the charge.)
Place and date of manufacture of propellant.
Place and date of filling.
Indication of propellant charges for hot climates.


Cases with steel covers for packing and transport, which are removed before loading, have neither labels nor stencilling relating to the propellant charge except the stencilling "Tp.25* C." imprinted on the base where applicable.  Details of the propellant are available, however, from the stencilling on the charge bags.

Stamping ont he base of the case is the same as that on the base of a fixed round, except that the caliber of the equipment is sometimes omitted.


Markins on the Cartridge Bags of a "Semi-Fixed" Round


These bags are marked similarly to the markings on fixed bags, except that the designation of the weapon is included.  In some cases the caliber is not included.  "Bleidraht im Beutel" indicates lead wire is included in the bag as a decoppering agent.

The number indicating the charge is marked prominently in black.  The letter "D" often follows this number and in some instances the marking is encircled by a red ring.


"Sonderkart" - Supercharge - With certain weapons additional charge sections, to be used for long ranges in place of those in the cartridge case, are supplied in cylindrical cardboard packages.  These sections are numbered in continuation of those supplied for use at normal ranges in the case.  Cardboard packages containing these additional charge sections are marked "Sonderkart" followed by the numeral of the section.


Marking of Primers for "Fixed" and "Semi-Fixed" Ammunition


Designation -- C followed by number.

Example: - C/33
nA - New Pattern
St - Steel


Marking of Flash Reducing Charges


This charge is found in a flat circular silk bag and is identified by the words "Kart. Vorl.", followed by the abbreviation indicating the weapon with which used and the weight of the charge in grams.

 

Next Time: 7.92mm to 30mm Projectiles

British Explosive Ordnance - Introduction and Fragmentation Bombs

British Explosive Ordnance

Introduction




Note: All present-tense mentions (the British Bombs currently in service, etc) refer to the at-the-time current 1946 Technical Manual.



Designation and Classification of British Bombs

British bombs are designated by purpose, weight, and mark number.  British mark numbers, which are always written in Roman numerals, correspond roughly to the modification numbers used by the US Navy, while the British weight designation corresponds to the US Naval mark number.  Minor changes in marks of British bombs are indicated by various symbols, consisting of lower case letters, capital letters, or asterisks.


The classification according to purpose is generally indicated by the initials of the specific type.  Thus, there is a series of antisubmarine bombs designated "A.S.", a series of general purpose bombs designated "G.P.", semi armor-piercing bombs designated "S.A.P.", aircraft depth charges designated "D.C.", etc.  Occasionally, when no appropriate initials can be used, the complete name of the bomb type is employed in the designation, as "Smoke", "Practice", etc.

Therefore, in order to describe a British bomb completely, the use, weight class, and mark number must be given in that sequence; eg, GP 250lb Mk V; IB 80lb Mk IV; Smoke 500lb Mk I; SAP 500lb Mk IIC.

The following are the type classifications of British bombs and the initials used to indicate them:

Fragmentation Bombs ----- F
General Purpose Bombs ----- GP
Medium Capacity Bombs ----- MC
High Capacity Bombs ----- HC
Deep Penetration Bombs ----- DP
Semi Armor-Piercing Bombs ----- SAP
Armor-Piercing Bombs ----- AP
Antisubmarine Bombs ----- AS
Aircraft Depth Charges ----- DC
Buoyancy Bombs ----- B
Incendiary Bombs ----- IB
Smoke Bombs ----- Smoke
Chemical Bombs ----- LC
Practice Bombs ----- Practice
Infantry Training Bombs ----- IT
Target Identification Bombs ----- TI
Anti-Tank Bombs ----- AT


Construction of British Bombs

British bombs generally are highly streamlined, although the later designs, such as the MC bombs, are parallel sided, resembling the American GP bombs in external appearance.   GP and MC bombs are usually of cast, one-piece construction, although some MC bombs may be built up in welded sections of cast or forged steel.  SAP and AP bombs are always forged in one piece and heat-treated for greater strength.  The exteriors of these bombs are well machined.  HC bombs are of thin-walled, "boiler plate", construction.



Fillings of British Bombs

A great variety of main fillings are used by the British.  The most common, however, are the following: Amatol for GO, MC, and HC types; TNT for SAP; and "Shellite" for AP bombs.  RDX/TNT combinations are also commonly employed in MC and HC bombs.  Current fillings are 60/40 Amatol HC, and desensitized Pentolite or RDX/TNT for all others.


Suspension of British Bombs

British bombs are suspended by a single suspension lug attached to the bomb body by machine screws.  Later designs of British bombs, such as the MC series, are fitted with additional dual suspension lugs for carrying in American planes.  Crutches or sway bars are used with larger size bombs.


British Tail Assemblies

A unique type of tail assembly is regularly employed by the British, consisting of a sheet-steel cone with a cylindrical strut attached by means of four sheet-steel fins.  The unique feature is the fact that the arming vanes are an integral part of the tail assembly.  They are attached to the tail pistol by means of a reach rod with a fork on its lower extremity engaging a similar fork on the tail pistol.  A special short trail,. originally designed for use in American built planes, is sometimes used to permit a greater bomb load.  A third type of tail assembly, rarely used, is designed to be employed in conjunction with certain tail fuzes which have their own arming vanes.  The arming vanes on this tail assembly are omitted, and the tail cone is truncated to give clearance to the vanes on the fuze.

Tail units are attached to bombs up to 1,000 pounds by a spring clip assembly, and to bombs of 1,0000 pounds and over by means of bolts.  Since each individual bomb is provided with its own specific tail unit, the bomb designation and tail number, which are stencilled on one of the tail fins, serve as a ready means of identifying the bomb.  The word "Mark" is omitted from both the tail unit and the bomb designation.  For example, the tail unit, No. 2 Mk I, used on the GP 500lb Bomb Mk IV, should appear on the tail unit as "No. 2 . 1, GP 500lb IV".

Color Markings and Stencilling of British Bombs

The following list gives the color markings employed on loaded British bombs.


F ------  Dark green overall with red band forward of light green band on nose.


GP ------- Dark green overall with red nose band and light green body band.


MC ------ Dark green overall with red nose band and light green band on base of ogive.


HC ------ Dark green overall with red nose band and light green band on forward portion.


SAP ------ Dark green overall with a white band just forward of a red band on the nose.


AP ------ Dark green overall with nose painted light green to point of greatest diameter; white band between two red bands on nose

DP ------ Dark green overall with red band near nose


AS ------ Dark green overall with red nose band and light green band at base of ogive


DC ------ Dark green overall with red nose band and colored band indicating filling forward of the suspension lug.

B ------ Dark green overall with red nose band and green band on ogive.

IB ------ Either dull red overall or have red nose end.  Most small sizes have a bright red band between two black bands around the nose.  Large sizes have a bright red band on the body and another on the after body.

Smoke ------ Dark green overall with a red band either around the nose or the after part of the body.


LC ------ Grey overall with colored bands to indicate chemical filler
Black band - Tear Gas
Green band - Lung irritant
Yellow band - Vesicant

Practice ------ White overall with two green bands around the tail cone.
IT ------ Dark green overall with red and green bands on nose


TI -- Black overall with red band at base of ogive.  Color of band around nose plug indicates the color of the candles.  A red cross on the after part of the body indicates that explosive candles are used.

Flares and Photoflash ------ Black overall with a red band near nose.

Cluster projectiles ------ Painted an overall color according to the type of small bombs carried.


HE filled bombs were originally painted yellow by the British.  The change to dark green was made at about the same time that the United States change to olive drab.  Consequently, yellow-painted bombs may still be found.


Complete information, including weight, type, mark number, filling, date filled, filling station and lot number will be found stencilled on the outside of all British bombs.  Although the location of the various stencillings differs with different bombs, the following sketch will indicate the information to be found and its approximate location on the outside of the bomb body.






Fragmentation Bombs


Introduction

There are only two sizes of fragmentation bombs now in use by the British.  These are the 8 pound, and several different marks of 20 pound fragmentation bombs, including a modified US 20lb fragmentation bomb.

The 20lb F bomb is nose fuzed only, and is similar in construction to the 40lb GP bomb.  It may be fitted with a standard tail for purposes of stabilization, or either a standard parachute attachment, or a special small parachute for use with a 500lb Cluster Projectile No.17 Mk II may be used.  The parachute attachments are designed to reduce the bomb's terminal velocity and so insure detonation of the bomb on impact before ground penetration takes place.

Fragmentation bombs are generally painted dark green overall with a red band and a light green band around the nose end.

These fragmentation bombs are used principally against personnel.

F. 8lb Mk I (Obsolete), and Mk II (Service)

Overall length: 4.2 inches

Body length: 3.02 inches

Body diameter: 5 inches

Wall thickness: 0.125 inches

Total weight: 8 pounds (approximately)
Charge/Weight ratio: 22% (approximately)

Fuzing: Tail Fuze No. 880 or 881

Parachute No: Tray No. 12, Mk I, with parachute

Color and markings:  Dark green overall
1/4 inch red band around after part,
1/2 inch light green band around center of bomb

Body Construction: The bomb body consist of a pot-shaped, cast-steel cylinder which is open at the top,  A steel neck ring, having internal threads to receive the adapter, is welded to the open end of the body.  The parachute tray is secured to the adapter.  Extending through the adapter fuze, which is enclosed by a paper tube 2 inches in diameter, extending through the bomb body.

Parachute: The parachute is 12 inches in diameter and is encased in a cylindrical steel tray having a diameter slightly less than the maximum diameter of the bomb body.  A safety pin extends through the parachute container, and is secured by a spring clip.

Explosive Components:

Main Filling: 1 and 3/4 pounds (approx.) of TNT, or RDX/TNT 60/40;
1 and 1/2 pounds (approx.) of Amatol 50/50 or 60/40, or Pentolite/D? (When filled with explosives other than TNT, a 1/4 inch topping of TNT is added)

Remarks: The Mk I Bomb has a smaller filling hole than the Mk II.  The Mk I was never fitted or adopted for service use.

F. 20lb Stabilized Mks I and II (Obsolescent), Mk III (Service), and Mk IV (Obsolescent)

Overall length: 21.8 inches

Body length: 11.9 inches

Body diameter: 3.95 inches

Wall thickness: 0.35 inches
Tail length: 9 inches
Tail width: 3.83 inches

Total weight: 20 pounds (approximately, with pistol)
Charge/Weight ratio: 15%

Fuzing: Nose Pistol No. 29, 34, 88, or 45; Nose Fuze No. 873

Color and markings:  Dark green overall
1/2 inch red band around nose
1 inch light green band 4 inches from the nose

Body Construction: This bomb has a stream-lined, one-piece, cast-steel body, with the nose end open to take the exploder container.  The rear end is reduced to form a spigot for taking the tail assembly.  The boss on the spigot is tapped and threaded to receive the tail-securing rod.  The exploder container is cemented in position, and locked by a locking screw.

Tail Construction: A cylindrical strut is attached to the tail cone by four fines.  The tail is secured to the body by a tail rod screwed into a boss on the body spigot, and passing through a threaded adapter on the narrow end of the tail cone.  The locking nut and spring washer at both the outer and inner ends of the rod lock it in position.

Suspension:
-Mk I: Carried 12 in Small Bomb Containers, or on Light Series bomb carrier if fitted with a suspension lug.

-Mk II: Carried 12 in Small Bomb Containers, or on Light Series bomb carrier if fitted with suspension lug or band.

-Mk III: Suspension lug welded on bomb body at center of gravity for carrying on Light Series bomb carrier; can be carried 12 in Small Bomb Container.

Explosive Components:
Exploders: CE and TNT pellets. (CE only being used now)

 Main Filling: 3.3 pounds of TNT or RDX/TNT (When RDX/TNT is used, a 1/4 to 3/8 inch topping of TNT is used in the nose.

Remarks: The Small Bomb Container, 160lb, contains eight of these bombs.  The Small Bomb Container, 250lb, will hold 12 of these bombs.  These bombs are no longer being manufactured.  However, they may be encountered in the field.  They are being replaced by the 8lb fragmentation bomb.

In the Mk IV Bomb the exploder system was changed to use only CE pellets, and a special retarded tail was incorporated.

F. 20lb Parachute Mks I and II (Obsolescent), and Mk III (Service)

Same as previous entry except as follows:

Fuzing: Nose Pistol No.33

Color and markings:  Dark green overall
1/2 inch red band around body 1/2 inch from nose
1 inch light green band 4 inches from the nose

Tail Construction: The parachute tail unit consist of a tail tube with a cylindrical strut connected to its rear portion by four fins.  The parachute, which is housed in a fabric cylinder, is contained in a tail tube.  A loose-fitting metal cover in the after end of the tube is attached to the fabric cylinder.  The parachute cords are connected to a wire rope secured to an eyebolt which connects the tail adapter and the body.  The tail adapter is secured in the front end of the tail tube by four screws.  When dropped, the metal end cover in the tube is blown off by the air slip, and acts as a pilot parachute to pull the main parachute out of the tube.

 Explosive Components: Filling:
-Mk III: 3 pounds (approx.) RDX/TNT
-Mk I and II: 3.3 pounds TNT

F. 20lb For No.17 Mk II Cluster Only (Service)

Overall length: 14.5 inches

Body length: 11.9 inches

Body diameter: 3.9 inches

Wall thickness: 0.35 inches

Total weight: 20 pounds (approximately)
Charge/Weight ratio: 15%

Fuzing: Nose Fuze No. 873

Color and markings:  Dark green overall
1/2 inch red band around nose
1 inch light green band around body

Body Construction: This bomb has a stream-lined, one-piece, cast-steel body, with the nose end open to take the exploder container.  The rear end is reduced to form a spigot for taking the parachute attachment.  The exploder container is cemented and locked in position.  The No.873 Nose Fuze is locked in position by a multi-tab washer.

Tail Construction: No tail is used with this bomb, which is especially designed to be used only in the No. 17 Mk II Cluster.  It has a short parachute attachment, secured to the body spigot by a threaded stud.  The parachute tray houses an 8 inch diameter fabric parachute with six pairs of rigging lines; each pair terminating in a whipped eye.  These eyes pass through holes in the tray and are threaded onto a metal circlip(?), which is secured on the underside of the tray.  A lid over the parachute in the ? held in position by the fuze of the bomb behind it.  When the cluster opens, the air slip displaces the lid, which pulls the chute free of the tray.

Suspension: This bomb has no suspension lugs, as it is used only in the No. 17 Mk II Cluster.

Explosive Components: Two TNT, and two perforated CE pellets.

 Main Filling: 3.1 pounds (approx.) of TNT

Remarks: The bomb is issued only in clustered form, and, when clustered, the fuze has no safety pin fitted.  Hence, care should be exercised in dealing with any individual bombs which might break loose from a cluster in handling.

US 20lb Fragmentation Bomb, Modified

Overall length (fuzed): 16.2 inches

Body length: 3.64 inches

Body diameter: 11.3 inches

Wall thickness: 0.56 inches
Tail length: 4.9 inches
Tail width: 3.64 inches

Fuzing: US Nose Fuze AN-M 104, or AN-M 120

Tail No: No.14 Parachute Housing

Color and markings:  Olive drab body, yellow nose and tail

Body Construction: This bomb consists of a US 20lb Fragmentation Bomb, which has been altered by the attachment of a special British parachute housing.  The bomb consist of a cast-steel nose and tail sections threaded to a seamless steel inner tube.  Helically wrapped around this inner tube is a heavy, drawn-steel wire to provide effective fragmentation.  The nose ? sections are threaded internally; the form to receive the nose fuze, and the latter to receive the parachute housing.

Tail Construction: The British No. 14 Parachute Housing consist of a cast-aluminum tray containing a 12-inch diameter parachute.  The tray is closed by a loosely fitting metal lid to which the parachute is attached by a short loop of cord.  The shroud lines of the parachute are fitted through holes drilled around the bottom edge of the tray, and are secured by a metal ring passed through the loops of the lines.  Leading from the parachute is an arming line, spliced to the arming wire from the fuze.  Release of the parachute withdraws the arming wire from the fuze, allowing the fuze to arm after a few seconds delay.

Suspension: Although the bomb is provided with a single, U-shaped, steel eyebolt welded to the bomb body for individual suspension, these bombs will be carried by the RAF in Cluster Projectiles No. 23 Mk I and No.24 Mk I.  In these clusters the nose of one bomb bears against the parachute lid of the bone behind it, holding the lid in place until the cluster opens.  The air slip then removes the housing lid, which acts as a pilot parachute and pulls out the 12 inch diameter parachute by which the bomb is suspended.

Remarks: Because of the extreme sensitivity of the Fuze AN-M 104, an extra spring, located outside the fuze body beneath the pressure plate, is added when this fuze is employed in these bombs by the RAF.

  

Next Time:  General Purpose Bombs

Italian Explosive Ordnance - Cartridge Cases

Italian Explosive Ordnance

Cartridge Cases



 It is the Italian practice to have more than one weight for the normal charge for a particular equipment.  These are referred to as 1st, 2nd, and 3rd normal charge.  In terms of weight, these represent decreasing values.  The charge may be a flashless type or nonflashless.  A flashless charge is obtained by the inclusion of bags containing potassium chloride.  Two types of marking and coloring systems were used.

The Old System had:

A. Colored rings on the base of the cartridge to refer to the propellent charge.

Red ---------- 1st normal charge
Blue ---------- 2nd normal charge
2 black rings ---------- 3rd normal charge
Red and White ----------- 1st flashless charge
Blue and White ----------- 2nd flashless charge
2 black half rings ---------- 3rd flashless charge
Green and White ----------- Special charge for star shells


B. Colored triangles on the base.

Black ---- 1st class condition
Green ---- Near end of its life
Yellow ---- Practice



C. Other marks

Green circle ---- AA
White ----- Star Shell
C.L. ----- Tracer fitted


On 76/17 and smaller calibers, there is insufficient space for complete rings and so color letters give details.

D. On the bags are the following general markings relating to propellent.

1. Initial of manufacturer
2. Lot and date of manufacture
3. Place and date of proof
4. Place and date of filling





The New System:

The type of charge is indicated by a number in brackets, as follows:

[1] - 1st normal charge
[2] - 2nd normal charge
[3] - 3rd normal charge

If the charge is flashless, there is a half black ring on the base.  A complete black ring indicates a special charge for light projectiles, usually a 3rd normal charge.

The following signs have indicated significance:

Black circle ----- AA
Black triangle ----- 1st class condition
Black square ----- 2nd class condition
Black diamond ----- Near end of life
Black star ----- Star shell
C.L. ----- Tracer fitted

75/13mm Mountain Gun Cartridge Case

Overall length: 129 mm
Overall diameter at mouth: 77.2 mm
Width of rim: 4 mm
Diameter at rim: 85 mm
Weight of empty case: 0.67 kilograms
Igniter: 10 g black powder
Primer: Percussion Primer M29 or M35








75/18mm Mountain Howitzer Cartridge Case

Overall length: 185 mm
Overall diameter at mouth: 78.5 mm
Width of rim: Unknown
Diameter at rim: 90.2 mm
Weight of empty case: 0.83 kilograms
Igniter: 10 g black powder
Primer: Percussion Primer M29 or M35

  

75/27mm Field Gun Cartridge Case

Overall length: 185.4 mm
Overall diameter at mouth: 78.5 mm
Width of rim: 3.6 mm
Diameter at rim: 90.2 mm
Weight of empty case: 0.835 kilograms
Igniter: 10 g black powder
Primer: Percussion Primer M29 or M35









75/32mm Light Field Gun Cartridge Case

Overall length: 334.1 mm
Overall diameter at mouth: 78.5 mm
Width of rim: 3.6 mm
Diameter at rim: 90.2 mm
Weight of empty case: 1.4 kilograms
Igniter: 10 g black powder










77/28mm Field Gun Cartridge Case

Igniter: 10 g black powder
Primer: Percussion Primer MO8 P.B. 29 or 35











100/17mm Light Field Howitzer Cartridge Case

Overall length: 132 mm
Overall diameter at mouth: 103.6 mm
Width of rim: 4 mm
Diameter at rim: 115 mm
Weight of empty case: 1.21 kilograms
Primer: Percussion Primer M29 or M35

Remarks: This cartridge case and loadings are also used for the 100/17mm Mountain Howitzer.

105/14mm Light Field Howitzer Cartridge Case

Overall length: 135 mm
Overall diameter at mouth: 110.9 mm
Diameter at rim: 122 mm
Weight of empty case: 1.76 kilograms
Igniter: 25 grams black powder
Primer: Percussion Primer M29 or M35





105/28mm Gun Cartridge Case
 

Overall length: 135 mm
Overall diameter at mouth: 110.9 mm
Diameter at rim: 122 mm
Weight of empty case: 1.76 kilograms
Igniter: 25 or 30 grams black powder with 5 grams of lead foil as a de-coppering charge
Primer: Percussion Primer M29 or M35

Remarks: Most cases for 105mm caliber guns are the same, but the propellent loading varies.  This same type of case and loading is used for the 105/32mm gun.







149/12mm Heavy Field Howitzer Cartridge Case

Overall length: 100 mm
Overall diameter at mouth: 157.2 mm
Diameter at rim: 171 mm
Weight of empty case: 1.8 kilograms
Igniter: 25 g black powder
Primer: Percussion Primer M29 or M35

149/13mm Heavy Field Howitzer Cartridge Case

Overall length: 221 mm
Overall diameter at mouth: 151.9 mm
Width of rim: 6 mm
Diameter at rim: 164.7 mm
Igniter: 25 g black powder
Primer: Percussion Primer M29 or M35








152/37mm Gun Cartridge Case

Overall length: 767 mm
Overall diameter at mouth: Unknown
Width of rim: Unknown
Diameter at rim: 180 mm
Weight of empty case: 9.72 kilograms
Igniter: 50 g black powder
Primer: Percussion Primer M35

Remarks: The charge of the propellent varies with the type of projectile used.










380/15mm Heavy Howitzer Cartridge Case

Overall length: 855 mm
Overall diameter at mouth: 390 mm
Width of rim: Unknown
Diameter at rim: 420 mm
Weight of empty case: 44 kilograms

Next Time: Italian Hand and Mortar Grenades