WP in CMAK

[Mr. Tittles]

Lieutenant Colonel JOE L. BOURNE, 168th Infantry.

"It is suggested that at least a platoon or company of

chemical mortars (4.2) be provided for each infantry regiment while

in combat in terrain such as we have in Italy, and for terrain such

as we will undoubtedly have to conduct future operations over.

The chemical mortar proved itself a highly valuable weapon on

the ANZIO Beachhead. It has greater range than our 81mm mortar.

The result of its fire is highly demoralizing to enemy troops.

German prisoners refer to the 4.2 mortar as the 'silent death',

because the fragments of the shell apparently splinter up much finer

than our 81mm mortars and a small splinter can pass through a man's

body almost without leaving a mark. The Germans do not like the

chemical mortar.ഊIt is realized that the chemical mortar is an organic part of

our army chemical warfare section, but we are firmly convinced it

can be used to great advantage with the infantry regiment either

attached or preferably to become a part of the T/E organizational

set-up of an infantry regiment."

Interesting observation about the large HE payload finely fragmenting the round.

[Mr. Tittles]

First Lieutenant DAVID B. AYRES, 135th Infantry.

"The 60mm mortar is a fine little weapon. It would help if

there were smoke shells available; they could be issued on the basis

of two per mortar in the basic load."

More info that 60mm WP or Smoke was either rare/non-existant.

From..

LESSONS LEARNED IN COMBAT

NOVEMBER 7-8, 1942 SEPTEMBER 1944

ALGIERS - FONDOUK CASSINO - ANZIO - ROME

HILL 609 - BENEVENTO CIVITAVECCHIA

VOLTURNO RIVER CECINA - ROSIGNANO

MT. PANTANO LIVORNO

HEADQUARTERS

34th INFANTRY DIVISION

APO 34 US ARMY

SEPTEMBER 1944 ITALY

CONFIDENTIAL

[Mr. Tittles]

Captain ALBERT J. HOIHJELIE, 135th Infantry.

"A white phosphorus rifle grenade can be made from a regular

AT rifle grenade and a WP hand grenade. These were used to a good

advantage at ANZIO. They should be made up by an ordnance company.

[Mr. Tittles]

The 29th Division's solution relied on the firepower and maneuver of small, closely coordinated combat teams. Each team consisted of a single tank, an engineer team, and a squad of infantry reinforced by a light machine gun and a 60-mm mortar from an infantry company's weapons platoon. Before the attack, the infantry and engineers occupied the hedgerow that served as the jump-off position for the assault (see figure 3). The attack began when a Sherman equipped with pipe devices nosed into the hedgerow and opened fire on the Germans with main gun and machine guns. The Sherman first fired a white phosphorous round into the corners of the opposite hedgerow to eliminate German heavy machine-gun positions. The tankers then systematically sprayed machine-gun fire along the entire base of the enemy hedgerow. The 60-mm mortar supported the attack by lobbing shells into the fields directly behind the German positions. The infantry attacked when the Sherman opened fire with its machine guns. The squad moved through the hedgerow deployed on line and advanced across the open field using standard methods of fire and movement. The infantry stayed away from the hedgerows on their flanks to avoid enemy grazing fire. The Sherman continued to support the attack until the infantry's advance masked the tank's machine-gun fire. As they closed on the German positions, American infantrymen threw hand grenades over the hedgerow to kill or confuse German defenders on the opposite side. Simultaneously, the Sherman backed away from its firing position, and the engineers einplaced demolitions in the holes left by the Sherman's pipe devices. After the explosives blew a hole in the hedgerow, the Sherman moved forward to provide close support to the infantry squad. The tankers and infantrymen then flushed the hedgerow of any remaining defenders and prepared to continue the attack. The engineer team and machine-gun and mortar crews then displaced forward to support the next assault.

http://www-cgsc.army.mil/carl/resources/csi/doubler/doubler.asp#61

Take notice of the word 'eliminate'. I will expand on this later.

[ October 26, 2003, 01:17 PM: Message edited by: Mr. Tittles ]

[EnglishRanger]

Just to add my 2 cents worth about WP.

In Iraq we were under heavy indirect fire for a while, the officers with nothing better to do were counting shells. They got to over 300 before they lost count.

During this time only 1 WP was dropped and it landed 20 feet from my alpha team leader, he heard it coming and dropped to the floor. It burst away from him and he took no ill effects. Everyone felt the heat, even from a hundred meters.

The blast hit a metal wall and splattered all over it, burning off the paint and eating a bit of the metal it seemed (I was never close enough to get a good look!).

The only significant thing was that the PL was about to call "Gas, gas gas" as we were briefed it may come and this was new. It was only because one of our history channel geeks said "Cool, willy pete" that the PL held his tongue. Simply nobody had ever seen it before in real life, West Point doesn't teach everything it seems, despite what the Os say!

Anyway in my albeit limited experience WP is very rare, less than 1% of shells fired. And the smoke lasted barely a minute and caused no casualties.

I have no idea what it came from, we too everything up to 155mm but I am sure it was smaller calibre than that. Our geek said probably 120mm mortar but I have no idea.

[Mr. Tittles]

CMAK-IRAQ?

I find the post entertaining but not applicable. I cant believe that the US fields soldiers/officers who are unaware of WP. Anyone with M224 training should know its one of the rounds.

As far as WP being a rare round, well.....

(2) Obscurants (smoke, white phosphorous, tear gas) are especially useful in urban

combat. The Russians used significant amounts of smoke and white phosphorus to mask

the movement of forces. Every fourth or fifth artillery or mortar round was either smoke

or WP. WP also had a toxic effect, easily penetrating Chechen protective masks.

http://www.mega.nu:8080/somans/mcwp3-35.3/appj.pdf

[ October 26, 2003, 09:23 PM: Message edited by: Mr. Tittles ]

[EnglishRanger]

Mr. Tittles I agree my post is not applicable but thought some may be vaguely interested in real life WP experience. I say it is rare as they were throwing everything but the kitchen sink at us but only 1 WP round out of hundreds. And everyone in the army knows of WP, however recognising it when it is fired at you is another thing. Nobody there had experience of having biological or chemical weapons fired at them either, what those shells looked like when they explode for example, so I can quite agree with any commander who errs on the side of caution when calling for guys to mask up.

[ October 26, 2003, 11:15 PM: Message edited by: EnglishRanger ]

[Mr. Tittles]

Sorry meant the M224.

Since the round was heard coming in, perhaps it wasnt a mortor round? If it splashed predominately in one direction, maybe it was a light arty shell?

Did the US forces use any WP?

Dont be so touchy. You, after all, like to call people geeks.

[EnglishRanger]

Guess I was a bit touchy, I apologise. I personally saw nobody use WP from our side but then I wasn't involved in firing the indirect, only recieving. I think they want to minimise its use as Iraqis bleeding looks better(or less damaging from a PR standpoint anyway) than Iraqis burned up on CNN. Nearly all shells blasted in the same general direction, the FOs got out there to do crater analysis but it was inconclusive. It could've been a light mortar, or gun or whatever, I personally didn't see it. They did have light mortars at first but we took them out right away with snipers, not sure what range their system had but we kept them with their heads down for a long way. Most stuff was coming from over 5 clicks out if I recall. As to the sound you can hear everything come in, I cannot describe the difference between mortars and arty, perhaps mortars are a higher note, it is hard to remember, suffice to say you can tell the difference, incidently, unlike the movies you get maybe a half second whistle before they hit! As for the geeks, I myself am one and the geek refered to above is my best friend, maybe tech nerd or grog would be better, either way he'd take it as a compliment!

[ October 26, 2003, 11:18 PM: Message edited by: EnglishRanger ]

[Mr. Tittles]

http://www.spearhead1944.com/amerpg/ammo1.htm

Basic ammunition loads for 3rd Army weapons

From: Operation Overlord, 3rd US Army Outline Plan, Annex No.13,G-4 Plan

Notes:

1. no 60mm smoke

2. 4.2" gets 50% WP smoke

3. 81mm WP infantry get 15%

4. 81mm WP HT armor gets 75% smoke

5. Sherman gets a mix of smoke 10%WP/5%HC

6. 105mm Smoke is 15%, a mix of smoke 50%WP/50%HC

Interesting that HE is listed as a mix for some weapons just as it is a mix for smoke. I would assume that 81mm HE mix is lt/hvy bombs (and 81mm HT armor would load up on hvys) but what would the 105mm HE mix be?

[ October 27, 2003, 09:26 AM: Message edited by: Mr. Tittles ]

[CMplayer]

Originally posted by EnglishRanger:

The only significant thing was that the PL was about to call "Gas, gas gas" as we were briefed it may come and this was new. It was only because one of our history channel geeks said "Cool, willy pete" that the PL held his tongue.

LOL. I love this kind of anecdote. 'Cool, willy pete'! Damn

[athkatla]

Originally posted by Determinant:

{snipped} but such precisely targeted shooting is beneath the dignity of the Royal Regiment of Artillery and considered unsporting.{snipped}

Bit of an oxymoron there, 'precisely targetted shooting' and 'Royal Artillery' and yes, I was an MFC with 1 R Anglian

[/QB]

[Mr. Tittles]

Originally posted by Mr. Tittles:

http://www.spearhead1944.com/amerpg/ammo1.htm

Basic ammunition loads for 3rd Army weapons

From: Operation Overlord, 3rd US Army Outline Plan, Annex No.13,G-4 Plan

Notes:

1. no 60mm smoke

2. 4.2" gets 50% WP smoke

3. 81mm WP infantry get 15%

4. 81mm WP HT armor gets 75% smoke

5. Sherman gets a mix of smoke 10%WP/5%HC

6. 105mm Smoke is 15%, a mix of smoke 50%WP/50%HC

Interesting that HE is listed as a mix for some weapons just as it is a mix for smoke. I would assume that 81mm HE mix is lt/hvy bombs (and 81mm HT armor would load up on hvys) but what would the 105mm HE mix be?

The data shows that WP is as common a round as HEAT or Cannister.

[Mr. Tittles]

Originally posted by John D Salt:

It would be nice if the modelling of smoke could ultimately show the difference between WP bursting smoke, pumice/oleum or chemical bursting smoke, and base-ejection smoke.

Looking through a couple of Ian Hogg's books shows the following natures of smoke shell to have been available for British, American and german WW2 artillery:

"British & American Artillery of World War 2", Ian Hogg, A&AP, London, 1978.

18 pdr gun -- WP bursting smoke

25 pdr gun how -- BES (4), BE TI and an incendiary (thermite) round. WP developed but not issued

3.7" mtn how -- WP bursting smoke

95mm how -- BES (3), BE TI

4.5" how -- WP bursting smoke and BES

4.5" gun -- no smoke

60 pdr gun -- no smoke listed

5.5" gun -- BES (4) "rarely issued", BE TI probably never

6" 26 cwt how -- no smoke listed

6" gun -- no smoke listed

7.2" how -- no smoke

8" how -- no smoke listed

9.2" how -- no smoke listed

12" how -- no smoke listed

75mm pack how -- WP bursting smoke, FS bursting smoke (titanium tetrachloride)

75mm gun -- WP bursting smoke

105mm how -- WP bursting smoke, FS bursting smoke, BES (3) HC

4.5" gun -- no smoke

155mm how M1917, M1918 -- WP bursting smoke, FS bursting smoke (sulphur trioxide), BES (3)

155mm how M1 -- WP bursting smoke, FS (titanium tetrachloride) bursting smoke, BES (4)

155mm gun -- WP bursting smoke, FS (titanium tetrachloride) bursting smoke

8" how -- no smoke listed

8" gun -- no smoke listed

240mm how -- no smoke listed

57mm RR -- no smoke listed

75mm RR -- WP bursting smoke

3-in anti-tank gun -- trailing smoke HC (hexachlorethane/zinc)

"German Artillery of World War 2", Ian Hogg, A&AP, London, 1975.

7.5cm leIG -- TI bursting smoke (blue)

15cm SIG -- no smoke listed

7.5 cm GebK 15 -- no smoke listed

7.5cm GebK 36 -- dyed HE

10.5cm GebH -- TI smoke

7.5cm FK 16 na -- no smoke listed

7.5cm leFK 18 -- pumice/oleum bursting smoke

7.5cm FK 38 -- no smoke listed

7.5cm FK 7M85 -- pumice/oleum bursting smoke

10.5cm leFH -- pumice/oleum bursting smoke, TI sugar/dye bursting smoke (blue), BES(1)

10cm K 17 -- no smoke listed

10.5cm leK 41 -- no smoke listed

10cm sK -- pumice/oleum bursting smoke

15cm s FH -- pumice/oleum bursting smoke

12.8cm K -- no smoke listed

15cm K -- no smoke listed

17cm K -- no smoke listed

Lg 21cm Mrs -- no smoke listed

21cm Mrs -- no smoke listed

21cm K -- no smoke listed

24cm H 39 -- no smoke listed

24cm K -- no smoke listed

28cm H -- no smoke listed

35.5cm H M1 -- no smoke listed

42cm Gamma H -- no smoke listed

BES (n) = base-ejection smoke, number of smoke candles shown in parentheses

BE TI = base ejection target indicating

TI = target indicating (coloured smoke)

Several things seem worthy of note. First, the Western allies appear to have a substantial edge on the Germans in smoke-making ammunition. Almost all German smoke rounds are bursting smoke using a pumice/oleum mixture, which I doubt is effective as the chemical compounds used in Anglo-American BES and some bursting smokes. The only German BES shell mentioned uses only one candle, and they seem to have issued no WP.

Smoke rounds are not issued for anti-tank guns of any nationality except the US 3-inch gun, and this is an unusual type which generates smoke in flight. It was apparently intended for use on SP equipments.

As far as artillery is concerned, smoke rounds seem to have been almost exclusively the province of the field artillery; the 5.5" smoke rounds saw little service, and only the Americans seem to have produced smoke for medium and heavy pieces.

I have not been able to guess exactly why Hogg refers to FS as being filled with sulphur trioxide in one case and titanium tetrachloride in others.

Finally, if AH's "Patton's Best" game is to be trusted, the 75mm gun as mounted in the Sherman should also have an HC bursting smoke round. The usual American practice seems to have been , very sensibly, to design a single pattern of bursting carrier shell capable of being filled with WP, a smoke compound or a chemical warfare agent.

Who's got smoke round information for Soviet artillery? Italian? Japanese? French? Anyone else?

All the best,

John.

Its interesting that many guns listed, both in your data and the Third Army data, do not have smoke shells. Is this modeled in the game?

[flamingknives]

The vast array of German guns aren't quite represented in CM, and the sIG is given smoke.

Off hand, I don't know about the heavier calibres as I don't use them that much.

[Mr. Tittles]

http://www.fas.org/man/dod-101/sys/land/m722.htm

Notice the modern 60mm WP.

Very thin wall construction, efficient WP packing and small burster needed. Also small fuze.

[Mr. Tittles]

http://search.yahoo.com/search?p=M302A1+60mm+Smoke+Cartridge+⊂=Search&ei=UTF-8&fr=fp-top

Most interesting

UNITED STATES MARINE CORPS

ANVANCED INFANTRY TRAINING COMPANY

SCHOOL OF INFANTRY

PSC BOX 20161

CAMP LEJEUNE, NORTH CAROLINA 28542 – 1061

27 June 2000

STUDENT OUTLINE

AMMUNITION AND FIRING TABLES

:

LEARNING OBJECTIVES:

TERMINAL LEARNING OBJECTIVES: Without the aid or references, but in accordance with FM 23 – 90.

1. Recognize the different types of mortar ammunition.

2. Prepare 60mm and 81mm mortar ammunition for firing.

3. Identify the procedures for storing mortar ammunition in the field environment.

4. Acting as a gunner fire the 60mm and 81 mm mortar.

5. Identify the procedures to burn increments.

6. Determine the elevation, charge, and maximum ordinance for a specific mission.

ENABLING LEARNING OBJECTIVES: Without the aid or references, but in accordance with FM 23 – 90 and Mortar Gunnery.

1. Identify the standard NATO marking of mortar ammunition.

2. Identify the nomenclature of the 60mm and 81mm mortar ammunition

3. Identify the different types of fuzes for the 60mm and 81mm mortar ammunition

4. Given a TFT with a range covered by two different charges, select the charge that would best enhance the mission.

5. State and define the two types of firing tables.

1. DESCRIPTION OF MORTAR AMMUNITION

a. Mortar ammunition is classified as semi-fixed complete. Semi-fixed complete ammunition is characterized by accessible propelling charges. This allows the charge to be varied by removing an element of it, and gives a greater flexibility in choosing a trajectory. Part of the complete propelling charge for mortar rounds consist have either bagged charges, “C” shaped charges, or sheets of highly combustible material, which are attached to the fin assembly. Ammunition is complete if it has all the necessary components to fire. For mortars, such ammunition is a cartridge, but is more commonly called a round.

b. Based upon use, the principle classification of training and service ammunition for the 60mm, and the 81mm mortar are:

(1) High Explosive (HE): The round is used against personnel, and light material targets.

(2) Whit Phosphorus (WP) / Red Phosphorus (RP): The WP / RP round is for use as a screening, signaling, casualty producing or incendiary agent.

(3) Illumination (ILLUM): The illumination round is for use in night missions requiring illumination for assistance in observation.

(4) Training Practice (TP): The training practice round is for used for training forward observers. The shell is filled with a small black powder pellet and plaster of paris that produces a small white cloud upon impact.

(5) Training: The training round is used when training mortar crews. It has inert filler and is propelled by ignition cartridge only.

2. IDENTIFICATION:

a. Labels and colors identify ammunition. Each cartridge is clearly labeled with the caliber, filler, type, lot number, and appropriate warning labels.

b. A lot number is assigned to each lot of ammunition produced by a manufacturer. Ammunition of the same lot should be stored and fired together. Lots should not be mixed if possible. Each category of ammunition has a distinctive color.

(1) High Explosive (HE): Olive drab with yellow markings.

(2) White Phosphorus (WP): Light green with red marking.

(3) Red Phosphorus (RP): Light green with black marking.

(4) Illumination (ILLUM): White with black marking.

(5) Training Practice (TP): Blue with white markings.

(6) Training: Bronze with white markings.

3. 6Omm MORTAR AMMUNITIOIN:

a. High Explosive (HE):

(1) M720 Cartridge

Max range: 3490 meters

Limitations: Cannot be fired above charge 1 in hand held mode

Rate of Fire: Maximum……….30rpm (for 4 minutes)

Sustained………..20rpm

Components: Fuze-multi-option, M734

(2) M888

Max Range: 3490 meters

Limitations: Cannot be fired above charge 1 in handheld mode.

Rate of Fire: Maximum………30rpm (for 4 minutes)

Sustained………..20rpm

Components: Fuze-Point detonating (PD), M935

(3) M49A4 Cartridge

Max Range: 1930 meters

Limitations: Short rounds may occur when fired in temperatures

below freezing.

Rate of Fire: Maximum…30rpm (for 1 minute) then 18rpm

(for next 4 minutes)

Sustained………8rpm

Components: Fuze-PD, M525 series

Remarks: Do not fire above charge 3 in handheld mode.

b. White Phosphorus (WP):

(1) M302A1 Cartridge

Max Range: 1630 meters

Limitations: Short rounds may occur when fired in temperatures

below freezing.

(2) M722 Cartridge:

Max Range: 3490 meters

Limitations: Can only be fired up to charge 1 in handheld mode.

c. Illumination (ILLUM):

(1) M83A3 Cartridge

Max. Range: 931 meters

Limitations: Cannot be fired below charge 2.

Components: Fuze-Time M65 series

Remarks: Provides about 330,000 candlepower illumination

For 33 seconds.

(2) M721 Cartridge

Max Range: 2950 (burst)

Components: Fuze-Multi-time super quick M776

d. Training:

(1) M69

Remarks: Cartridge has inert body and can be reused.

4. 60mm MORTAR FUZES:

a. The fuzes used on 60mm mortar ammunition are made to cause the fired round to function at the desired time or point. The fuzes used with 60mm mortar ammunition are classified as impact, fixed-time, multi-time super quick, or multi-option.

(1) Impact Fuze: This fuze will cause the round to function when it comes in contact with an object. The 60mm uses point detonation (PD) impact fuzes. Point detonation fuzes function either immediately upon impact, called super quick (SQ), or 1/20 of a second (.05 secs) after impact called delay (D). The impact fuze is used with the HE, WP, and practice rounds.

(2) Fixed-time fuze: This fuze will cause the round to function at a prescribed time after the round is fired. The fixed –time fuze is non-adjustable and is only used with illumination round

(3) Multi-time super quick (M776): This fuze will cause the round to function at a specified time, or impact. The fuze may be set to function anywhere from 0 to 54 seconds. This fuze is found on M721 illumination.

(4) Multi-option fuze (M734): The multi-option fuze for the M720 HE round can be set to function as proximity burst (PROX), near surface burst (NSB), impact burst (SQ) or delay burst (D). The setting can be changed any number of times before firing without damaging the fuze.

5. 81mm Mortar Ammunition:

a. High Explosive (HE):

(1) M821 Cartridge

Max Range: 5608 meters

Components: Fuze, Multi-option M734

(2) M889 Cartridge

Max. Range: 4800 meters

Components: Fuze, Point Detonating M935

b. White Phosphorus (WP

(1) M374A3

Max Range: 4800 meters

Components: Fuze, Point Detonating M567, M524 or M532

c. Red Phosphorus (RP)

(1) M819 Cartridge

Max. Range: 4875 meters

Components: Fuze, Mechanical time Super quick M772

d. Illumination (ILLUM)

(1) M853 Cartridge

Max. Range: 5100 meters

Components: Mechanical Time Super quick M772 or Time M768

Remarks: Provides a minimum of 600,000 candlepower for at least 60 seconds.

(2) M301A3 Cartridge

Max Range: 3150 meters

Components: Fuze Time M84A1

Limitations: Cannot be fired below charge 3

Remarks: Provides a minimum of 500,000 candlepower for at least 60 seconds.

e. Training

(1) M879

(2) M880

(3) M68

(4) SABOT

Max. Range: 5600 meters

Remarks: Type 1, resembles M821 HE

Type 2, resembles M889 HE

There is a smoke charge in the fuze which produces a

flash on impact.

6. 81mm MORTAR FUZES:

a. The fuzes for the 81mm mortar are made to cause the round to function at the desired time or point. There are 5 different types of fuzes used and they are: Impact Fuze, Proximity Fuze, Multi-option Fuze, Time Fuze and Mechanical Time Super quick Fuze.

(1) Impact Fuze: The fuzes will cause the round to function when it comes in contact with an object. The 81mm mortar uses point detonation (PD) impact fuzes. Point Detonating fuzes function either immediately upon impact, called super quick (SQ), 1/20 of a second (.05) after impact called delay (D). The impact fuze is used with HE, WP and practice rounds.

(2) Proximity (variable time): The proximity (VT) fuze is a complete radio, transmitter and receiver. It is manufactured to cause the round to detonate when it approaches the target. There is no time or distance setting on the fuze. It sends out radio waves and will function when the radio wave is reflected back to the receiver upon approach to the object. The variable time means that it will function at a variable distance for the target. The fuze will detonate the round for 1 to 6 meters above the target depending upon the angle of approach and the texture of the targets terrain. Dense vegetation will increase the height of burst, while spars vegetation will lower the height of burst.

Proximity: M532 fuze

Functions: Prox / Impact

(3) Multi-option Fuze: The multi-option fuze for the M821 HE round can be set to function three different ways. The setting can be changed any number of times before firing without damaging the fuze.

a. Proximity burst (3 – 13 feet)

b. Near surface burst (0 – 3 feet)

c. Impact burst or delay burst (.05 seconds)

(4) Time Fuze: The time fuze used for illumination rounds will function when the set time has expired after firing. When a failure occurs within the fuze prevention it for functioning at the specified time it will not function upon impact.

Time: M84 series fuze

Functions: Airburst

Settings: 0 – 25 (M84)

0 – 55 (M84A1)

(5) Mechanical Tome Super quick (M772 Fuze): The MTSQ fuze will function at the end of a specified time or upon impact. The MTSQ fuze can be set to function upon impact or it may be set to burst anywhere from 0 to 55 seconds after it is fired. This fuze has a time element and also a back up point detonation element that will cause the fuze to function on impact if the time setting shall fail or if the time setting is set longer than the time of flight. This fuze will also function as a point detonating fuze if the time element is set of safe.

Mechanical Time Super quick: M772 Fuze

Functions: Airburst/Impact

Settings: 4 – 55 seconds (½ second intervals)

7. CARE AND HANDLING OF MORTAR AMMUNITION:

a. Handling: After the ammuition bearer prepares the round, it is handed to the assistant gunner, who is standing, sitting or kneeling facing away from the direction of fire on the side of the mortar. He grasps it firmly and checks to ensure if is properly prepared and contains the correct charge.

b. Loading: After checking the cartridge for the correct charge and removal of the safety wire the assistant gunner upon hearing the command “HALF LOAD” from the gunner, squad leader or section leader inserts the round into the muzzle, fin assembly first with his right hand. He will insert the round up to the gas ring and should be careful not to disturb the lay of the mortar.

c. Firing: On the command “FIRE” the assistant gunner releases the round and follows through with his hand down the front of the cannon and away form the traversing mechanism and turns his head away from the blast.

TRANSITON: NOW THAT WE HAVE COVERED THE CARE AND HANDLING THE AMMUNITOIN LET’S MOVE ON TO THE STORAGE.

8. STORAGE:

a. Improper storage causes most ammunition malfunctions. Extreme temperature causes mortar rounds to deteriorate very rapidly. This deterioration will normally affect fuzes and propelling charges. Affected fuzes will be duds. Affected propelling charges will cause a short rounds or rounds that are erratic in flight. There are two types of storage used and they are Depot and Field Storage.

(1) Depot Storage: This is the best type of storage because the temperature and the humidity can be controlled. This type of storage is found in ammunition depots that are permanent.

(2) Field Storage: Field storage must be temporary except in areas of dry, moderate temperatures. Mortar crewman in the field uses this type of storage. Always store ammunition under cover, 6 inches off the ground and in their original containers and boxes.

b. White Phosphorus rounds are stored separate from any other type of ammunition with fuze end up. Since white phosphorus liquefies at about 100 degrees Fahrenheit these rounds must be protected against any uneven re-hardening of the filler. An air cavity on one side of the round will cause instability in flight.

9. SAFETY PRECATIONS:

a. The following safety precautions must be followed when handling mortar ammunition:

(1) Ammunition is adversely affected by moisture and high temperature; give consideration to its protection from these conditions.

(2) The explosive elements in primers and fuzes are sensitive to strong shock and high temperatures and must be handled accordingly.

(3) Do not break the moisture resistant seal of the fiber container until the ammunition is to be fired.

(4) Do not attempt to disassemble the fuze.

(5) Protect the ammunition from mud, sand, dirt and water. See that the rounds are free of such matter before firing

(6) Do not allow the ammunition to be exposed to the direct rays of the sun for any length of time. More uniform firing is obtained when the rounds are kept at the same temperature.

(7) Remove the safety wire from the fuze just before firing.

(8) Do not handle duds. They are extremely dangerous because the fuze is armed and any movement of the round may cause it to explode.

10. DESTRUCTION OF UNUSED INCREMENTS:

a. Because of their high combustibility, be careful when igniting them. Do not allow excess increment to a designated place and destroy them as follows.

(1) Select a place at least 100 meters from the mortar position, parked vehicles, and ammunition piles.

(2) Pre-burn all dead grass or brush with in 100 feet or more around the burning place.

(3) Prohibit smoking or fires around ammunition, increments or the place of burning

(4) Do not burn increments in piles, but spread them in a train 1 to 2 inches deep, 4 to 6 inches wide. From this train extend a starting train of single bagged increments laid end to starting train with not less then 2 feet of inert material (dry grass, leaves, etc.). Ignite the material.

(5) Do not look directly into the burning increments. The intense light may do damage to your eyes.

11. AMMUNTION AND FUZE SELECTION:

a. In order to be successful on the battlefield as a mortar leader you must be able to determine the type of ammunition, and fuze needed to engage a target. In addition to ammunition and fuze selection you must:

i. Determine what targets to hit and when.

ii. Decide how to attack the target.

iii. Understand what effects your fires will inflict.

iv. Understand the effects the terrain will have on your ammunition and fuze selection.

b. High explosive ammunition. When mortar rounds impact, they throw fragments in a pattern that is never truly circular and may even be irregular, based on the rounds angle of fall, the slope of the terrain, and the type of soil. However, for planning purposes, each mortar HE round is considered to have a circular lethal bursting area. The type of mortar ammunition and fuze fired determines the bursting area.

c. Fuze settings. The decision as to what type of fuze and setting to use depends on the enemy’s position.

1. Exposed enemy troops that are standing up are best engaged with impact (IMP) or near surface burst (NSB) fuze settings. The round explodes on, or near, the ground. Shell fragments travel outward perpendicular to the long axis of the standing target.

2. If Exposed enemy troops are lying prone, the proximity (PRX) fuze setting is most effective. The rounds explode high above the ground, and the fragments coming downward are once again traveling perpendicular to the long axis of the target.

3. The PRX setting is also the most effective if the enemy is in open fighting positions, without overhead cover. Even PRX settings will not always produce effects if the positions are deep.

4. When the enemies are located under heavy canopy or in fighting positions with overhead cover the delay (D) fuze setting is most effective. Light mortars will have little effect against overhead cover; even medium mortars have limited effect. Heavy mortars can destroy a bunker with a hit or near miss.

d. To determine the number of rounds needed to cover a target in lethal fragments the planner uses the effects table. This table gives information on the average lethal areas, in square meters, of mortar HE ammunition against various targets. These figures can be used to develop to mortar ammunition required re-supply rate. Planners determine the size of the target or objective area, and then divide the lethal areas of the needed to cover the target in lethal fragments. This gives a rough idea of the least number of rounds needed to cover the target area once.

e. Against a standing, platoon-size enemy unit, a 60mm mortar section that fires five rounds per mortar should inflict about 20 percent casualties. If the enemy is prone, these fires should inflict less than 10 percent casualties. This means that a 60mm mortar sections FFE should seldom consist of any less that five rounds from each mortar, and often will require more.

f. Impact fuzed rounds are normally the best for adjusting fire. If dense foliage prevents observation of the IMP fuzes round, NSB or PRX settings will cause the round to explode near the top of these trees where the burst can be observed. If there is a combination of snow cover and fog in the target area, making adjusting rounds difficult to see, the delay setting can be used for adjustments. This causes a plume of dirt or exposes the earth at the point of impact. The dark soil contrast with the fog and snow, making adjustments easier.

12. EFECTS OF TERRAIN ON HIGH EXPLOSIVE FIRES:

a. HE fires are the most common for destruction, neutralization, and suppression. Most mortar HE rounds can be fired with the M734 multi-option fuze. This fuze enables HE rounds to be detonated above the target surface, on the target surface, or after a short delay. Older ammunition that cannot use the multi-option fuze uses single or dual fuzes to achieve almost the same effects. These effects vary depending on the ground, target, and size of mortar fired.

b. Soft ground limits the effectiveness of surface burst HE rounds for light, medium, and heavy mortars (light mortars being limited the most). One foot of soft ground, mud, sand, or 3 feet of snow can reduce the effectiveness of surface burst HE rounds by up to 80 percent. Light mortar rounds can land close (within a few yards) to a target on this type of ground and still have no effect.

c. Hard, rocky soil and gravel actually increase the effectiveness of surface burst HE rounds. The rock fragments are picked up and thrown by the blast adding to the enemy’s casualties (heavy mortars throw the most rock fragments).

d. Dense woods cause impact fuzed HE rounds to detonate in the trees, producing airburst. This airburst can be dangerous to exposed troops since large wood splinters are added to the rounds metal fragments. Wounds caused by large wooden splinters are often severe. Extremely dense woods, such as triple canopy jungle, cause most impact fuzed HE rounds to detonate high in the trees without much effect at ground level.

13. EFFECTS OF COVER ON HIGH EXPLOSIVE ROUNDS:

a. Enemy forces will normally be either standing or prone. They may be in the open or protected by baring degrees of cover. Each of these changes the target effects of mortar fire.

b. Surprise mortar fire is always more effective that fire against any enemy that is warned and seeks cover. Recent studies have shown that a high casualty rate can be achieved with only two rounds against an enemy platoon standing in the open. The same studies required ten to fifteen rounds to duplicate the casualty rate when the platoon was warned by adjusting rounds and sought cover. If the enemy soldiers merely lay prone, they significantly reduce the effects of mortar fire. Mortar fire against standing enemy forces is almost twice as effective as fire against prone targets.

c. Proximity fire is usually more effective that surface burst rounds against targets in the open. The effectiveness of mortar fire against prone targets is increased by about 40 percent. The steeper the angle of the fall of the round, the more effective it is.

d. If the enemy is in open fighting positions without overhead cover, proximity fuzed rounds are about five times as effective as impact-fuzed rounds. When fired against troops in open fighting positions, proximity fuzed rounds are only 10 percent as effective as they would be against troops in open fighting positions, the charge with the lowest angle of fall should be chosen. If produces almost two times as much effect as the same round falling with the steepest angle.

e. If the enemy has prepared fighting positions with overhead cover, only impact fuzed and delay fuzed rounds will have much better effect. Proximity-fuzed rounds can restrict the enemy’s ability to move from position to position, but they will cause few or little casualties. Impact-fuzed rounds cause some blast and suppressive effect. Delay-fuzed rounds can penetrate and destroy a position but must achieve a direct hit. Only the Army’s 120mm mortar with a delay fuze setting can damage a Soviet-style strongpoint defense. Light or medium mortar rounds cannot destroy heavy bunkers.

14. EFFECTS OF TERRAIN ON PROXIMITY-FUZED HIGH EXPLOSIVE ROUNDS:

a. The multi-option fuze functions best over open, firm soil. Snow or sand can cause it to function low or on impact. Water or frozen ground can cause it to function early. If proximity-fuzed rounds are functioning high, they are still effective. Using near surface burst setting on the fuze can reduce the HOB. Choosing the steepest angle of fall possible cannot increase it except by choosing the steepest angle of fall possible.

b. Proximity-fuzed rounds fired over built up areas can detonate if they pass close by the side of a large building. They can also function too high to be effective at street level. (Impact-fuzes are most effective in heavy built areas)

c. In dense jungle or forest, proximity fuzes detonate to early and have little effect. Impact fuzes achieve airburst in dense forest, and delay fuzes allow rounds to penetrate beneath heavy canopy before exploding.

15. SUPPRESSIVE EFFECTS OF HIGH EXPLOSIVE ROUNDS:

a. Suppression from mortars is not as easy to measure as the target effect. It is an effect produced in the mind of the enemy that prevents him from returning fire or carrying on his duties. Inexperienced or surprised soldiers are easily suppressed than experienced, warned soldiers. Soldiers in the open are much more easily suppressed that those with overhead cover. Suppression is most effective when mortar fires first fall; as they continue, their suppressive effects lessen. HE rounds are the most suppressive, but bursting WP mixed with HE has a great psychological effect on the enemy.

b. The suppression effects table can be used to help the planner determine the effects of suppressive fires. The table is used for determining suppression effects o HE rounds only.

16. EFFECTS OF MORTAR FIRE AGAINST VEHICLES:

a. Mortar fires by themselves are not normally effective against vehicles, especially armored vehicles, but they can be most effective when combined with direct fires of anti-tank weapons. Mortar fires force the armored vehicle crewmen to button up, reducing their visibility and preventing them for firing heavy machine guns mounted outside the vehicle. This allows dismounted infantry to approach closer, within range to use their handheld anti-armor weapons.

b. Mortars are generally ineffective as a killer of tracked vehicles. Mortar fragments can damage exterior components of lightly armored scout vehicles, ATGM launchers, or self propelled or mobility kills are difficult to achieve without expending large amounts of mortar ammunition.

c. Against moving heavily armored vehicles like tanks or BMP’s, the best mortar fires can achieve is forcing the crew to button up. Against stationary tanks or BMP’s, bursting WP rounds form 81mm mortars can be effective. These rounds must make almost a direct hit on the target to cause any damage.

d. Point-detonating rounds are most effective against trucks. Their low-angle fragments do the most damage to tires, wheels, and engines. Bursting WP rounds are also effective if mixed with HE.

17. GUIDELINES FOR THE USE OF HIGH EXPLOSIVE ROUND:

a. The following guidelines are useful during the planning of mortar fires. As the battle progresses, the actual results should be reviewed and guidelines modified.

1. What is the enemy?

a. If the enemy is un-warned, standing in the open, fire one impact fuzed HE round from each mortar. Then fire the following rounds as proximity-fuzed.

b. If the enemy is prone or crouching in open fighting positions, fire all rounds as proximity fuzed.

c. If the enemy’s status is unknown, fire all proximity-fuzed rounds.

2. What is the ground in the target area like?

a. If the ground in the target area is soft, swampy, or covered in deep snow, fire proximity fuzed or near surface burst rounds.

b. On rocky and hard soil, fire a 50 percent mixture or proximity fuzed and impact fuzed rounds.

c. If the soil type is unknown, fire all proximity-fuzed rounds.

3. What is the vegetable in the target area like?

a. If the target is within forest, fire point-detonating fuzes for all rounds.

b. In extremely dense forest or jungle, fire point-detonating fuzes with 50 percent delay fuzes.

4. What is the enemy position like?

a. If the enemy is in bunkers, fire point detonating mixed with 50 percent delay fuze.

b. Do not depend on light or medium mortar fires to damage heavy bunkers or buildings.

c. Expert heavy mortar to destroy some heavy bunkers and damage others, but also expect to fire large amounts of ammunition.

18. WHITE PHOSPHORUS:

a. The bursting WP round provides a screening, incendiary, marking, and casualty producing effect. It produces a localized, instantaneous smoke cloud by scattering burning WP particles.

b. The WP round is used mainly to produce immediate, close point obscuration. It can be used to screen their enemy’s field of fire for short periods, which allows troops to maneuver against him. The 60mm WP round is not sufficient to produce a long lasting, wide area smoke screen, but the much larger WP round for the 81mm is.

c. The bursting WP round can be used to produce casualties among exposed enemy troops and to start fires. The casualty-producing radius of the WP round is much less than that of the HE round. Generally, firing HE ammunition than firing WP can produce more casualties. However, the WP burst causes a significant psychological effect, especially used against exposed troops. A few WP mixed into a fire mission of HE rounds may increase the suppressive effect of the fire.

d. The WP rounds can be used to mark targets, especially for attack by aircraft. Base ejecting smoke rounds, such as the 81mm M819RP round, produce a dispersed smoke cloud, normally to indistinct for marking targets.

e. All bulk filled WP ammunition needs special care when temperatures are high. The WP filler liquefies at temperatures of 100 degrees farenheight. Since the WP does not fill all the space in the cartridge, the result is a hollow space in the upper part of the cartridge, filler cavity. This can cause the round to become unbalanced and, therefore, unstable in flight. WP ammunition should be protected from direct sunlight, if possible. When stored at high temperatures, it should be stacked with the fuze up. Keeping the WP ammunition under cover, digging ammunition bunkers, opening only as many rounds as needed, maintaining proper storage, and monitoring the ambient temperature will reduce the chances of firing unstable ammunition. In climates of extremely high temperatures, WP ammunition should be fired only if taken directly from vertical storage. This does not apply to t the M252 mortar’s base ejection RP smoke rounds. The need no special vertical storage.

f. The effects of atmospheric stability can determine whether mortar smoke is effective at all or, if effective, how much ammunition will be needed.

1. During unstable conditions, mortar smoke and WP rounds are almost ineffective—the smoke does not spread but often climbs straight up and quickly dissipates.

2. Under moderately unstable conditions, base ejecting smoke rounds are more effective than bursting WP. The RP round for the 81mm burns for 2 ½ minutes.

3. Under stable conditions, both RP and WP rounds are effective. The higher the humidity, the better the screening effects of mortar rounds.

g. The M819 RP round looses up to 35 percent of it screening ability if the ground in the ground in the target area is covered, in water or deep snow. During extremely cold and dry conditions over snow, up to four times the number of smoke rounds may be needed than expected to create an adequate screen. The higher the wind velocity, the more effective bursting WP rounds are, and the less effective burning smoke rounds become.

h. If the terrain in the target area is swampy, rain soaked, or snow covered, then burning smoke rounds may not be effective. These rounds produce smoke by ejecting felt wedges soaked in red phosphorus. These wedges then burn out on the ground, producing a dense, long-lasting cloud. If the wedges fall into mud, water, or snow, they can be extinguished. Shallow water can reduce the smoke produced by these rounds by as much as 50 percent. Bursting WP rounds are affected little by the terrain in the target area, except that deep snow and cold temperature can reduce the smoke cloud by about 25 percent.

i. Although bursting WP rounds are not designed to cause casualties, the fragments of the shell casing and bits of burning WP can cause injuries. Burning smoke rounds do not cause casualties and have little suppressive effect.

19. ILLUMINATION:

a. Illumination rounds can be used to disclose enemy formations, to signal, or to mark targets

b. The 60mm illumination round does not provide the same degree of illumination, as do the rounds of heavier mortars and artillery. However, it is sufficient for local, point illumination. The small size of the round can be an advantage where illumination is desired in an area but adjacent to friendly forces that do not want to be seen. The 60mm illumination round can be used without degrading the night vision devices adjacent units.

c. The 81mm mortar can provide excellent illumination over wide areas.

20. SPECIAL ILLUMINATION TECHNIQUES

a. The following are three special illumination techniques that mortars have effectively used.

1. An illumination round fired extremely high over a general area will not always alert an enemy force that is being observed. However, it will provide enough illumination to optimize the use of image intensification (starlight) scopes such as the AN/TVS-4.

2. An illumination round fired to burn on the ground will prevent observation beyond the flare into the shadow. This is one method of countering enemy use of image intensification devices. A Friendly force could move behind the flare with greater security.

3. An illumination round fired to burn on the ground can be used to mark targets during day or night. Illumination rounds have an advantage over WP as target markers during high winds. The smoke cloud form a WP round will quickly be blown downwind. The smoke from the burning illumination round will continue to originate form the same spot, regardless of the wind.

TRANSITION: PROBE STUDENTS. UP TO THIS POINT WE HAVE COVERED MORTAR AMMO AND FUZES NOW LET’S GET IN TO FIRING TABLES.

21. FIRING TABLES:

a. The main purpose of firing tables is to provide the data required to bring effective fire on a target under any condition. Firing tables consist of pre-determined data for a specific type of mortar and ammunition. They are:

(1) Abridged

(2) Unabridged

b. Abridge Firing Table:

1. The abridged firing table consists of minimal information only. Abridged firing tables are normally in the form of printed cards found inside ammo boxes and whiz wheels. These firing tables should only be used if a Tabular Firing Table is not available. If the abridge firing table is used, insure that it contains all current charges and corrections. A minimum of three items of information can be found on this card:

i. Range

ii. Elevation

iii. Charge

c. Unabridged Firing Table:

1. The unabridged firing table normally comes in the form of a book known as a Tubular Firing Table (TFT). When selecting and using a TFT there are a few things you need to check for

a. Currency of the TFT – This is found on the bottom of the first page with an asterisk and statement telling you what TFT this replaces.

b. Ammunition and Mortar – Found on the front cover of the TFT. The computer must insure that he uses the correct TFT for the ammunition and mortar he is firing.

c. Changes – Changes are issued through the U.S. Army Firing Tables Branch in Aberdeen, Maryland. The changes need to be added to the TFT to keep it current and safe.

2. The TFT is broke down into an introduction, three parts and an appendix. The parts are further broke down into five tables, A through E. A through C deals with correction factors when working with the MET. The primary tables used for mortars will be Table D and Table E.

3. There are currently seven tabular firing tables that contain data for the 81mm and 60mm mortars. It is up to the unit to insure that these tables are maintained and up to date wit all issued changes. The firing tables that are currently being used are:

a. 81mm

i. FT 81-AI-3

ii. FT 81-AQ-1

iii. FT 81-AR-1

b. 60mm

i. FT 60-P-1

ii. FT 60-S-1

iii. FT 60-T-1

iv. FT 60-R-1

22. FT 81-AI-3:

a. The cover for FT 81-AI-3 reads a follows:

Mortar, 81mm: m29a1 and m29

Mortar, 81mm, Self-Propelled:

M125A1 and M125

Carrier, 81mm Mortar: Tracked, XM755

Firing

Cartridge, HE, M374A2 and M374

Cartridge, WP, M375A2 and M375

Cartridge, Illuminating, M301A3

Cartridge, Training, M68

b. Without the issued changes issued to this publication the user would assume that this TFT does not apply to the M252 81mm mortar. However, there are several changes that have been issued to this TFT that will allow us to use it they are:

i. Change 3 tells us to change the title to include the M252

ii. Change 4 tells us not to fire the M252 mortar system at elevations exceeding 1423 mils above charge three when firing this ammo.

iii. Change 5 tells us that the M374A2 HE, and the M375A@ are ballistically matched.

23. FT 81-AR-1:

a. The cover for firing tables FT 81-AR-1 reads as follows:

For

Mortar 81mm, M252

Firing

Cartridge, HE, M821

Cartridge, HE, M889

Cartridge, RP, M819

b. The changes issued to this publication is as follows:

i. Change 1 tells us to add Cartridge, TP, M879, and Cartridge, Illum, M853A1 to the title and gives us the firing data

ii. Change 2 gives us new data for the M819 RP round making the data in the TFT obsolete.

iii. Change 3 gives us to addition of two rounds and the data to fire them. Cartridge, HE, XM984, and Cartridge, HE, XM983.

iv. Change 4 tells us that the M821 and the M889 are ballistically matched.

24. FT 81-AQ-1:

a. The cover of the firing tables 81-AQ-1 reads as follows:

For

Mortar, 81mm: M29A1 and M29

Mortar, 81mm, Self-Propelled:

M125A1 and m125

Carrier, 81mm Mortar: Tracked, M755

Firing

Cartridge, HE, M374A3

b. The changes that are issued to the is TFT are:

i. Change 1 tells us to add the M252 to the title. It also tells us that the M374A3, and the M375A3 are ballistically matched.

25. FT 60-P-1:

a. The cover of the 60-P-1 reads as follows:

For

Mortar, 60mm: M224

Firing

Cartridge, HE, M720

Cartridge, HE, M49A4

Cartridge, TP, M50A3

Cartridge, Illuminating, M83A3

b. The issued changes to this TFT are:

i. Change 1 tells us to add the M888 round to the title. Change 1 also gives us corrections to use in conjunction with the data for the M720 for fire the M888.

ii. Change 2 tells us to add the Cartridge, Illum, and M721 to the title and includes the data to fire the M888.

iii. Change 3 adds the M302A2 WP to the title and informs the user that the data used to fire the M302A1 is also used to fire the M302A2.

iv. Change 6 adds the M766 TP round to the title and list the data to fire it.

v. Change 7 adds the M722 WP round to the title and tells the user that the data used to fire the M720 is also use to fire the M722.

26. HOW TO USE THE TFT’S:

a. When using the TFT’S follow the following procedures:

1. Insure that the firing tables match the ammunition being fired. (Check for changes)

2. Select the lowest charge. When selection charges always select the lowest on that will range the target. When conduction special missions choose the charge that will allow you to move the entire width/length of the target. To determine the lowest charge use on of the following methods:

a. Open the TFT to part 1 and turn back on page. This page is the Charge vs. Range chart. The chart can be used to determine the lowest charge to engage the target so that the user does not have to check each charge individually to determine the lowest one. To use the chart do the following:\

i. Find the range to the target by using the range bar at the bottom of the chart. The range bar is numbered every 500 meters from 0 to 5,000 meters.

ii. After determining the range on the range bar, place a straight edge at this point so that it crosses the charge lines.

iii. Determine which charge line the straight edge crosses first. This is the charge that will be used to enter the TFT.

NOTE: When using the range bar sometimes the user may have to open up two charges to determine the lowest charge.

b. Another method that can be used is to turn to page II in the TFT. There is a charge zone and range listed for the type of ammo being used. This table lists the minimum and maximum ranges for each charge.

3. Open The TFT to the lowest charge determined by on of the above methods. After turning to the correct charge go to table D or E. Go down the range column until you find the range to the target. Read across to column four to determine the elevation that will be placed on the gun to engage the target.

27. MAINTENANCE OF PUBLICATIONS:

a. Using units should conduct a quarterly inspection of the TFT’S to insure that they are kept updated with issued changes. While firing using abridge firing tables it can also lead to safety hazards. Units should make every possible attempt to obtain and maintaining a set of unabridged firing tables.

b. Ordering of TFT’S can be accomplished through your unit S-3/S-1. When ordering use the following PIN numbers. Order with changes on through current for each publication to insure that you receive all changes.

FT 81-AI-3 PIN: 029822-000

FT 81-AR-1 PIN: 061636-000

FT 81-AQ-1 PIN: 050486-000

FT 60-P-1 PIN: 046120-000

NOTE: Do not use this outline as a reference to update your units TFT’S. Changes are issued frequently and not all changes are listed in this outline.

[ October 27, 2003, 12:16 PM: Message edited by: Mr. Tittles ]

[Mr. Tittles]

i. Although bursting WP rounds are not designed to cause casualties, the fragments of the shell casing and bits of burning WP can cause injuries. Burning smoke rounds do not cause casualties and have little suppressive effect.

Just in case you missed it.

[Mr. Tittles]

a. Light mortars are included in the preparation fires when ammunition, positioning, and the enemy situation permit. The commander keeps in mind that mortar ammunition fired early can be hard to replace later. Mortars should provide fires on the objective to support the final assault, especially if the direct support artillery is 155 mm. This allows indirect fire suppression of the enemy until the assaulting forces close to within about 50 meters (minimum safe distance). Assaulting forces can get closer to the enemy under the cover of small caliber mortar fire than would be possible with fires from medium or heavy artillery. A method that was used successfully in World War II was for the assaulting platoon to approach as close as possible to the objective while the mortars fire HE to suppress the enemy. On a prearranged signal by the assault force, the mortars switched to WP rounds and fired several in quick succession. The bursting WP rounds were the signal to the rifle platoon that the mortars were shifting their fires 50 to 100 meters beyond the objective. As soon as the last WP had round burst, the assault forces closed with the enemy. Not only do the WP rounds signal the shifting of fires, but also the smaller casualty-producing radius provides a margin of safety for the assault force. The psychological effect of the WP and the smoke produced combine to create confusion among the enemy during the critical moments when the friendly forces are exposed. This requires well-trained and practiced mortar crews, as well as close coordination between the mortar section and the assaulting force.

https://hosta.atsc.eustis.army.mil/cgi-bin/atdl.dll/accp/in0491/lesson7.htm

Good lessons. I am beginning to think the 60mm WP was probably used around the fall 1944.

[Mr. Tittles]

http://www.tigerforcerecon.com/nam9.htm

We began to set up for the night. Lt. Christian began to set up delta tangos, and I could hear him call his first shot, intended to burst over the next finger to the side of us, several hundred feet away. The radio whispered “Shot, over.”

Lt. Christian said “Shot, out.”

Off in the distance I could hear the muffled boom of the single gun firing the smoke round. I thought that I needed to get my spot finished so I could make rounds, and pass out medicines, and my other usual night time chores, before it got any darker. zszszszszszszszsZSZSZSZSZSWHAMBANG!

So fast that I could hardly grasp what was happening/had happened, the smoke round came in and burst just a few feet above us, possibly below the canopy of trees. A piece struck within our perimeter in a fraction of a second after the round exploded. Instant pandemonium! I scrambled from my half-erected hooch, and crouched there looking around to see who had been hit. There were so many cries of pain and confusion that I knew someone had been hit. I made my way to the closest position to mine, and found there two men lying against trees, each with several small shrapnel wounds in their arms and sides. Their hooch was collapsed onto a still form. I said I needed a flashlight, and the men who had come out of the hooch began to cry out, “What for, Doc? He’s dead, man, forget it man , he’s dead!”

I asked the other medics present to take care of these men, took a proffered flashlight, dropped to my knees, and lifted the poncho. I pulled the poncho down over my head, and shoulders and after making sure the edges were sealed against the light, I prepared to turn on the flashlight. I could smell burned flesh, and feces in the air, and in this tight enclosure, with the body of the man just inches from my face could feel the heat of his body, and that from the chunk of smoke round buried in the dirt below. I clicked the switch, and there revealed before me was the young soldier’s back, laid open and sealed by the burning chunk of steel, from his shoulders to his hips. Like an anatomy lesson, his organs lay there in perfect display, the smoke from the round curling up from the ground, his body slumped forward. Instantly dead.

I turned off the light, but that image was to be imprinted on my mind forever. I dropped the poncho back over the still form and walked away. The other medics wrapped his poor broken body in the poncho and prepared to evac him out in the morning.

30 years later I attended my first 101st Airborne Division Reunion. While there I met men I hadn’t seen or spoken to in the entire interim. This story came up for discussion. One of the men who was there at the time told me that the boy who died was the same young trooper that had fallen out earlier that day. I cannot attest to that, but if true, I cannot help but wonder at the irony of this young man’s fate. Not wanting to go further, the struggle that he endured that day to keep up, only to be killed that night by an errant round. Was this just bad luck or could some sort of future memory have been at work, trying to keep him from a place he did not want to go, because of the end that waited for him?

[Mr. Tittles]

The previous gory post illustrates that, indeed, bursting type WP or HC could ruin your day. 3 casualties from a close proximity smoke round. 1 Fatality.

[JonS]

Originally posted by Mr. Tittles:

... To be honest, I do not know the rifling/spin rate but in guns like the sherman 75mm I have heard 20,000 RPM. ...

I guarantee you that any sized piece of metal that WAS spinning at 10,000-20,000 RPM at 2.1 inches that strikes you would be memorable. ...

Without passing comment on what you do or don't know and the value of your guarantees, I will point out that the spin-rate of the 4.2" mortar rounds was on the order of 8,000rpm (actually a bit less, but near enough).

Relevant data for an approximation can be found here and here.

Regards

JonS

[ October 28, 2003, 02:47 AM: Message edited by: JonS ]

[Mr. Tittles]

Thanks JonS. Actually, the spin rate would be a function of the amount of charges (translation muzzle velocity and rotational velocity varying together) also but I am too lazy at the moment to do the math.

[Mr. Tittles]

I would like to start the final part of this threads discussion matter. Namely the direct fire gun/howitzer bursting WP shell. The star witness will be the Sherman 75mm gun and its M64 round with the M57 fuze.

I have given the matter some thought and would like to bring up some details regarding the 4.2 inch WP round and present it here again as 'evidence'. This evidence will help develop my theory (call it whatever you like) about the direct fire WP rounds.

Evidence suggests that these 4.2 inch rounds, on detonation , would reduce the shells to a base plate and turn the shell walls into fragments. Since the HE burster charge used in these WP shells was of less power than the HE shell, the fragments produced would PROBABLY be larger. evidence suggests that the HE fragments were finely divided.

Many people might stop right there and claim 'Hey, big fragments, less velocity, less effect'. And they would be somewhat correct,for this type of round. The 4.2" mortar round descends at a steep angle. It usually lands in a somewhat vertical orientation. Unless it can be detonated at a height above ground, like a tree burst, its burster charge/fragmentation is localized (think of a downward cone directed into teh ground). Since the 4.2" is slow moving (well this is range/velocity dependant), this 'down-ward fragmentation' effect is attenuated. Anyway you cut it, the bottom line is that the 4.2" WP WOULD break up on impact and had a fragmentation effect. The fragmentation effect is aided by the height of detonation and spinning of the shell. The spinning will by the laws of physics, give a added velocity to the fragments produced.

OK. Lets wipe the mystified looks off our faces and 'turn' to the direct fire 75mm WP shell. I say 'turn' because it lands, generally, at a very flat relationship with the ground. It compares to the 4.2 " as a higher velocity, greater spin rate.

Here's my main contention (if you havent already guessed it). The direct fire bursting WP type of shell acts as a sort of mutant. It behaves with properties similar to a fragmentation/cannister round! This behaviour is in addition to the heat/burning/incindiery effect of the WP.

I would contend that the burster, on breaking up the shell casing, releases the WP agent (aided by not just the burst but by the rotational speed) and the shell fragments/fuze/ect continue forward in a deadly cone pattern.

Cannister rounds exhibit this behaviour. They are always likened to shotguns but shotguns are smoothbore. Cannister rounds will develop a cone distribution pattern. the balls in the cannister round closest to the rifling are the ones that cone out, the ones near teh center will travel forward along the line of aim.

It may be a leap of faith but I believe this is what might be happening in spin stabilized burster shells that have comparatively less HE than a normal HE shell.

The effect on the target end would be devastating. Not only from the WP and the small concussion but the directed hail of metal flying into the target.

[Mr. Tittles]

Lets look at some examples of 75mm WP aginst target types:

1. Units in buildings. Infantry trying to take cover in most unfortified structures hit by a 75mm WP round (SQ fuze setting), would be treated to a hail of large shell fragments coming through the wall. Most of the WP would be distributed on the extarior wall with some coming through. If a delay fuze was used, the detonation would be internal to the building and the WP would be maximized in effect in an enclosed area.

Example: The ATG in a house. This was discussed by the tankers in one of the links I posted. They must have inspected the crew closely afterwards because they reported that they just found a pair of feet. This supports the forward directed blast/fragmentation effect.

[ October 28, 2003, 01:45 PM: Message edited by: Mr. Tittles ]