Infantry Mortars

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Kingfish
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Re: Infantry Mortars

#16

Post by Kingfish » 08 Jun 2011, 15:13

I could be wrong, but I think the U.S variant of the 4.2" mortar (or perhaps the ammo) is a different beast than the Commonwealth.

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Saxon Cross
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Re: Infantry Mortars

#17

Post by Saxon Cross » 08 Jun 2011, 15:31

David W wrote:Anyone got any idea of the weights of the three different mortar rounds (2", 3" & 4.2") and how much amotol was contained within each?

2 inch Light Mortar
Deployment: 1938
Length 65 cm
Weapon wt: 10.65 kg (airborne version 4 Kg)
Bomb wt: 1 kg
Range 500 yards

3 inch Medium Mortar (ML)
Deployment: 1920s
Length: 130 cm
Weapon wt: 57 Kg
Bomb wt: 4.5 Kg (compare to other mediums: German: 3.5 Kg; US: 3.1 Kg)
Early range: 1600yds
Long range: 2800yds (called the LR or Mk II, Dec 1943)

4.2 inch Heavy Mortar
Deployment: July 1942
Length: 64 - 68 inches
Weapon wt: 324 lbs
Bomb wt: 9.1 Kg
Early range: 3200 yards (July 1942, El Alamein)
Mid date range: 4400 yards (July 1943, Sicily invasion)
Late range: 5600 yards (June 1945)

David W wrote:Am I right in thinking that the Light Infantry Mortars of 3" calibre replaced the 2"?
Or did the two co-exist?

Was the Heavy Infantry Mortar 4.2" used throughout WWII?
The light 2 inch and medium 3 inch and heavy 4.2 inch were completely different weapons for different purposes.
One was never intended to replace the other. They all co-existed once the heavy was introduced.



Saxon


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Saxon Cross
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Re: Infantry Mortars

#18

Post by Saxon Cross » 08 Jun 2011, 17:57

The 2 inch mortar is often said to have been primarily a smoke and flare (illumination) mortar; but just as many HE rounds as smoke rounds were produced (on demand) during the course of the war.

About 22.7 million 2 inch mortar HE rounds were made during the war, compared to 22.9 million 2 inch mortar smoke rounds (these were smoke rounds made for the infantry mortar, so does not include the 2 inch smoke rounds made for AFV 2 inch smoke dischargers).

2 inch HE rounds were often used with great affect, and I've seen medal citations which specifically noted the skilled use of a 2 inch mortar. Some blokes would even brace the thing against a building or tree and shoot the rounds horizontally.

Saxon

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Kingfish
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Re: Infantry Mortars

#19

Post by Kingfish » 08 Jun 2011, 20:47

Saxon Cross wrote:Some blokes would even brace the thing against a building or tree and shoot the rounds horizontally.
I remember reading about Canadian troops using the same technique at Ortana, with soldiers shooting out one upper story window across the street and into another.

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Re: Infantry Mortars

#20

Post by David W » 09 Jun 2011, 01:10

Thanks Jon.

Delta Tank. That sounds like an awful lot of TNT for a shell weighing about the same as that of a 25Pdr, over four times a much, can that be right?

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Re: Infantry Mortars

#21

Post by JonS » 09 Jun 2011, 04:54

barrel pressures and muzzle velocities are MUCH lower in mortars than field guns.

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Re: Infantry Mortars

#22

Post by Jabberwocky » 09 Jun 2011, 08:10

Some more information on the 2", 3" and 4.2" mortars, courtesy of the excellent coverage of British equipment on the WWII Equipment website

http://www.wwiiequipment.com/index.php? ... &Itemid=59

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David W
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Re: Infantry Mortars

#23

Post by David W » 09 Jun 2011, 10:17

Thanks Saxoncross & Jabberwocky.

I'm still looking for the amount of H.E filler (T.N.T) in each round. (Where's Tony Williams when you want him? :wink: :) )

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Re: Infantry Mortars

#24

Post by Saxon Cross » 09 Jun 2011, 20:49

David W wrote:Thanks Saxoncross & Jabberwocky.

I'm still looking for the amount of H.E filler (T.N.T) in each round. (Where's Tony Williams when you want him? :wink: :) )
Actually the 3 inch and 4.2 inch used Amatol 80/20 (so only had 20% TNT).

What specifically do you need the filler weight for, what's the end use, because I may have the info you're looking for, from a solid War Office source.

Cheers,
Saxon

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David W
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Re: Infantry Mortars

#25

Post by David W » 09 Jun 2011, 21:07

What specifically do you need the filler weight for, what's the end use, because I may have the info you're looking for, from a solid War Office source.
Just to compare the relative shell weight/H.E filler weight ratio.

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Re: Infantry Mortars

#26

Post by Saxon Cross » 09 Jun 2011, 21:58

David W wrote:
What specifically do you need the filler weight for, what's the end use, because I may have the info you're looking for, from a solid War Office source.
Just to compare the relative shell weight/H.E filler weight ratio.
That's it?

I have a War Office document that has the results of scores of studies, which show the effectiveness of the various mortar rounds (including the 2 inch, 7.5lb and 10lb 3 inch, and 4.2 inch mortar rounds), indicating the percent chances for wounds/incapacitation at various radii (and sq ft effectiveness), and the effectiveness of each round on different types of terrain and cover; how much armour the fragments can penetrate at various ranges and so on.

Although the doc has filling types, it doesn't have weight.

Saxon

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David W
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Re: Infantry Mortars

#27

Post by David W » 09 Jun 2011, 22:19

I have a War Office document that has the results of scores of studies, which show the effectiveness of the various mortar rounds (including the 2 inch, 7.5lb and 10lb 3 inch, and 4.2 inch mortar rounds), indicating the percent chances for wounds/incapacitation at various radii (and sq ft effectiveness), and the effectiveness of each round on different types of terrain and cover; how much armour the fragments can penetrate at various ranges and so on.
Actually, that would be very interesting, as I have only ever seen those in the past for artillery, starting with the 25Pdr & getting bigger. So something similar on the mortars would be great. Thanks.

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Re: Infantry Mortars

#28

Post by Saxon Cross » 09 Jun 2011, 23:24

Hi David,

I was asking what you needed specifically because I am willing to cherry pick info you need and post it; but I'm hesistant to share the whole document.

Over the years I have amassed a large collection of WW2 documents and info from various sources, and I often share these on various forums. I could potentially just upload my hard drive and make it all available, but much of this info required a lot of searching and was hard to come by.

I guess I'm saying tell me specifically what you want to know, and I will share what I've got; or if you want the whole document, I'd be willing to swap it for something :)

I may be interested in any WW2 doc you might have. I'm a WW2 wargamer, and my main interests are the European ground war and associated AFVs weapons/equipment. I have a particular interest in the British army, but also the German US and Soviet forces. I also love graphics of vehicles.

The document is 35 pages in PDF format, written for wargamers, and is drawn from specific War Office documents that are referenced:
eg. W/O 290/489


Here's roughly what's on it:


Compares 7½lb & 10lb 3" mortar bomb

Lethality of artillery (25 Pdr, 75mm and 105mm)

Fragmentation (mortars, 3 inch, 40mm & 20mm AA guns, medium arty, GP bombs et al)

Lethality of 3" mortar (cast iron vs steel)

Ground cover Influence on HE projectiles (includes 3 in mortar and 25Pdr)

Sherman M3 gun and British 95mm HE effectiveness

White phos as anti personnel

2 Inch mortar performance

Smoke effectiveness

Night visibilty

25 Pdr dispersion/accuracy

Bombardment casualty study

Mine effectiveness

HE airburst effectiveness

ATk accuracy

Flamethrower effectiveness

Wire cutting ability of HE

Weight of small arms fire to neutralize various targets

Performance of grenades

Comparing effectiveness of rifle, LMG, SMG

Comparison of 3 inch and German 8cm mortars

Effect of HE on personnel (2 Pdr, 6 Pdr, 75mm, 25 Pdr)


And lots more…


Feel free to PM me if you want the whole doc, or just let me know on this thread if you just want specific info.


cheers,
Saxon

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Re: Infantry Mortars

#29

Post by Delta Tank » 10 Jun 2011, 21:20

David W wrote:Thanks Jon.

Delta Tank. That sounds like an awful lot of TNT for a shell weighing about the same as that of a 25Pdr, over four times a much, can that be right?
David,

Sorry I have not got back to you, for some reason I do not get notified by e-mail on threads I have posted on. I have checked all my information, can't find where my e-mail address goes, still working on it. Will check weight, but If I recall correctly, it has been some years, ok, decades, but the weight was 27 lbs or so, TNT filler, got it from wiki, will check Ian Hogg.

Mike

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Re: Infantry Mortars

#30

Post by Delta Tank » 12 Jun 2011, 13:39

David,

My book by Ian Hogg does have filler weights, unfortunately he does not discuss mortars. I believe I have another book that he wrote, but can't find it off hand. I have a book entitled "Brassey's Artillery of the World" edited by Shelford Bidwell, he has mortars in his book, but no filler weights. Will continue to search.

Mike

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