# Soviet M1938 120mm mortar.



## davebender (May 10, 2012)

6km max range. 
.....10.5 cm leFH 18/40 howitzer = 12km.
about 12 rounds per minute. 
.....10.5 cm leFH 18/40 howitzer = 8.
Shell contains about the same amount of HE filler as a 105mm artillery shell.
285kg weapon weight. 
.....10.5 cm leFH 18/40 howitzer = 1,955kg.

The 120mm mortar used by Germany and the Soviet Union looks very impressive on paper. How well did it perform in combat?


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## Jabberwocky (May 10, 2012)

There is a very good write up of Finnish experiences with both Soviet 120mm and German 120 mm mortars here 

FINNISH ARMY 1918 - 1945: 120 MM MORTARS


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## davebender (May 11, 2012)

I'm surprised Germany didn't adopt that solution during 1935 when their army expanded from practically nothing to 36 divisions. It would have been a quick, inexpensive way to provide new infantry divisions with supporting artillery. When artillery production catches up with demand you can add some 10.5cm K18 weapons to each division for long range missions plus some of the heavier 15 cm sFH 18 howitzers.


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## tomo pauk (May 11, 2012)

While the 105mm howitzers were a significant leap forward when compared with 75-77mm light guns from ww1, they were all requiring the capable motor towing in order to be efficient - weapon weighted far more, requiring more crew, ammo + charges being notably heavier, piece for piece. 105mm stuff was not able to be manhandled meaningfully, 120mm mortars could be manhandled. The cost of the mortar was indeed negligible when compared with 105mm howitzers.
Interestingly enough, with 120mm mortar at hand, Soviets went for 122mm howitzers.


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## Shortround6 (May 11, 2012)

The 120mm mortars were a great addition to a units firepower. However with a range of just over 1/2 the range of 105 howitzer they could not provide the deep support for an attack or help with counter battery duties.


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## davebender (May 11, 2012)

That's why I suggested inexpensive 120mm mortars for general infantry support plus long range weapons like the 10.5cm K18 for long range missions. You get the best of both worlds. 120mm mortars can be pulled by almost anything. Two horse team, Kettenkraftrad and even the small 4WD VW Schwimmwagen would be adequate for towing a 120mm mortar cross country. Only the long range weapons would require artillery tractors. 

How do the mortars compare with 10.5cm howitzers for accuracy and sustained fire ability?


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## Shortround6 (May 11, 2012)

Sustained fire there probably isn't much to choose. Accuracy of most WW II mortars is pretty bad. 

The German 10.5cm howitzers weighed a bit under 2000kg in action, a bit more on the move. The 10.5cm K18 went over 5600kg in action and even more on the move. There were never going to be enough of them, especially considering that the 15cm s FH18 used the same carriage/recoil system. The 10.5cm K18 gun was a corp or army asset, it was not deployed on the divisional level. 

A problem with the 12 cm mortars is not the weight of the mortar but in supplying them with ammo. A Russian M1943 mortar weighs about 500kg (1100lbs)on the move. The shells weigh about 35lbs each, bare without shipping containers/boxes. 32 unboxed bombs weigh more than the Mortar on it's wheels. The impact of the 12cm mortar bombs is certainly impressive but you are not going to keep them feed for very long without motor transport. a six tube battery firing 6 bombs per minute (under 1/2 peak rate of fire) for ten minutes will use up 6.3 tons of mortar bombs. Add in the shipping/transport containers and the logistics get real interesting.


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## Tante Ju (May 12, 2012)

Mortars are effective for direct support. But have limitations.

However Shortrand point on ammo supply is very good. Also worth considering at what area a 10,5cm with double range can provide fire support immidate compared to a mortar, and how many more mortars you need to cover the same area with equal firepower.

I would say 3-4 times as many mortars (crews, logistics) and deep they cannot support.


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## davebender (May 12, 2012)

Since 1914 German infantry have relied on 105mm howitzers firing danger close to defeat enemy attacks. That won't work if 120mm mortar accuracy isn't similiar to 105mm howitzer accuracy.


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## Shortround6 (May 12, 2012)

A study of the Modern (post 1995) US 120mm mortar. Wartime mortars from both Germany and Soviet union ( and any body elses smooth bores) is not likely to be as good, in fact they could be considerably worse. Mortars at the time were not only viewed as a "cheap" substitute for artillery, their ammunition was viewed as "cheap" to produce too. This lead to cheaper materials and more allowable variations or tolerances than allowed for in Artillery ammunition. 

http://www.dtic.mil/ndia/2005smallarms/tuesday/trohanowsky.pdf


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## psteel (May 12, 2012)

German infantry given the choice between infantry guns or mortars went for the infantry guns. Not only were they much more accurate, they had much more stopping power when it came to enemy AFV/vehicle assaults. As I recall when the move away from the infantry guns to mortars was proposed by 1943, it was expected to replace each infantry gun with two mortars to make up for the loss of accuracy.


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## tomo pauk (May 12, 2012)

When the German Army was given such a choice? In one corner we have the lightest infantry gun (7,5cm), weighting 400 kg, able to propel the 6kg shell, and on the other corner we have the 120mm mortar weighting under 300 kg, mine weighting 2,5 times more, with range being 80% greater. Accuracy and stopping power vs. tanks with a shell fried at 210m/s is nothing to write home about; the traverse of 12deg also hampers firing vs. moving targets. Germans have had another choice, 105mm mortars, weighting 100 kg - 1/4th of the 7,5cm IG, range about the same, shell 20% heavier.


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## psteel (May 12, 2012)

The decision to go to 'infantry guns' was done in the late 1920s under the first rearmament drive and there was no modern 120mm mortar for another 10 years.The design for the original german 10cm mortar began in 1934 and ended in 1939 leading to mass producion later that year.

During the war the 120mm mortar was to replace the 150mm infantry gun, the 82mm mortar was to replace the 75mm infantry guns....btw both these guns had HEAT rounds by 1941/42. The 105mm mortar was specifically designed to fire chemical shells and all such weapons were under special units.

Bit of reseach might have helped?


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## Tante Ju (May 13, 2012)

Tomo, please for example tell me how you use a mortar to knock off a MG position in street fighting, when MG is on 2 level of 5 level building... just to illustrate in this case a IG is much better solution.


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## tomo pauk (May 13, 2012)

Well, sure enough I wouldn't be driving any towed stuff into the street, the MG would've have a live fire exercise with the gun it's crew. So, definitely not a plus for a towed IG.



psteel said:


> The decision to go to 'infantry guns' was done in the late 1920s under the first rearmament drive and there was no modern 120mm mortar for another 10 years.



Thanks.
Saying that 'there were no modern' this or that is a moot point; there was no ground breaking technology that would've prevent a design production of 120mm mortars, all the way between the world wars. All what was needed was Heer's requirement.



> The design for the original german 10cm mortar began in 1934 and ended in 1939 leading to mass producion later that year.



There you go 



> During the war the 120mm mortar was to replace the 150mm infantry gun, the 82mm mortar was to replace the 75mm infantry guns....btw both these guns had HEAT rounds by 1941/42. The 105mm mortar was specifically designed to fire chemical shells and all such weapons were under special units.



There was nothing preventing the 105mm firing HE mines, and those were issued anyway. Stating in one sentence 'mass production' and on the other 'all such weapons were under special units' is contradictory.



> Bit of reseach might have helped?



Of course, please do some research.


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## Shortround6 (May 13, 2012)

The small German infantry gun was used in street fighting at times. It was small enough to be pushed into position (around a corner) and had an armored shield. certainly not ideal at one or two block distances but perhaps at longer ranges?

The 1920s and early 30s were a period of ground breaking technology in many fields. Couple this with most armies around the world being way under funded and research and development was in fits and starts, as were tactics. 

Most WW I mortars looked like Junior cannon with breech mechanisms, elevating gears and recoil systems. 

7.58 cm Minenwerfer - Wikipedia, the free encyclopedia

17 cm mittlerer Minenwerfer - Wikipedia, the free encyclopedia

Mortier de 150 mm T Mle 1917 Fabry - Wikipedia, the free encyclopedia

Or they were a cheap and at times scary lot of equipment.

Stokes mortar - Wikipedia, the free encyclopedia

2 inch Medium Mortar - Wikipedia, the free encyclopedia

14 cm Minenwerfer M 15 - Wikipedia, the free encyclopedia

Some armies were still using the original Stokes in 1930 if not later. 

Basic Field Manual. Volume III, Basic Weapons. Part Four, Howitzer Company / prepared under the direction of the Chief of Infantry. :: Obsolete Military Manuals

The German infantry gun offered 3-4 times the range of some of these contraptions and better accuracy. In some cases _MUCH_ better accuracy. The 4 in Stokes mortar ( a chemical weapon) used a Similar design bomb as the 3 inch, basically a flat nosed can with propelling charge on the back. It was fitted with an "all ways" fuse as it tumbled in flight and could not be depended upon to land nose first. 

The French Company of Edgar Brandt took the basic Stokes mortar and through a number of improvements brought it up to the WW II standard. Most nations either bought mortars from Brandt or licensed them. Better, more areo dynamic bombs, Stronger barrels of better steel, improved sights and mounts and so on brought the mortar to what it was at the beginning of WW II. Ranges 2-4 times the WW I Stokes and better accuracy although that is saying much. In many cases the cheap approach compromised the actual usefulness of the basic design. Since firing stresses were less cast iron bodies could be used, cheaper but thicker walled (less HE) and did not fragment well. Stamped sheet metal fins sometimes riveted together. Thin fins will work but they are subject to handling damage and the resulting loss of accuracy (British 4.2 in mortar displayed a rather amazing and annoying habit, damaged fins would cause the bomb to tumble in flight but instead of causing random dispersion it caused the bombs to drop about 1000yds short, usually near the forward observer  

The also had to be a change in tactics and other changes in technology. Battalion/regimental support weapons existed because in WW I it was too difficult for the battalions/regiments to communicate with Brigade or Division headquarters to ensure heavy weapons (artillery) support whenever wanted/needed. In some cases the request for fire support was received but guns were already committed to supporting a different Battalion/regiment.

the capabilities of the weapons should be matched to the expected areas the unit is expected to cover. A battalion is expected to cover a certain length of frontage in defense and a rather smaller frontage in offence. It is weapons are expected to reach into the enemy area a certain distance. AS you go up in unit size the frontage is multiplied by the number of battalions but the depth of penetration into the enemies territory increases. An infantry battalion has no business trying to silence enemy guns 6-10 kilometers passed the front line even if they are shooting at them. That is a job for Divisional or Corp artillery.

The German guns were actually held at regimental level in a platoon of six and parceled out in pairs as needed or as the unit commanders saw fit. Since each Battalion had at least six 81mm mortars (if up to strength) the addition of a pair of 7.5cm infantry guns must have offered something the mortars couldn't supply.


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## davebender (May 13, 2012)

Actually it was done during WWI.

By 1914 the German Army was well down the road towards using indirect fire field howitzers ILO direct fire field guns. During 1915 7.7cm field guns began receiving a new carriage that allowed an elevation up to 40 degrees.

WWI German infantry still desired a few light artillery weapons that could place direct fire on an enemy MG position or other strongpoint so they adopted several different infantry guns. One consisted of a lightened 7.7cm field gun mounted on a new carriage with small wheels so it sat low to the ground. Another infantry gun consisted of captured Russian 7.62mm field guns modified in a similiar manner. There was general agreement that 75mm was the smallest useful HE shell. These direct fire infantry guns did not substitute for indirect fire mortars or howitzers which Germany also had plenty of.


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## tomo pauk (May 13, 2012)

Shortround6 said:


> The small German infantry gun was used in street fighting at times. It was small enough to be pushed into position (around a corner) and had an armored shield. certainly not ideal at one or two block distances but perhaps at longer ranges?
> 
> <......>
> 
> The German guns were actually held at regimental level in a platoon of six and parceled out in pairs as needed or as the unit commanders saw fit. Since each Battalion had at least six 81mm mortars (if up to strength) the addition of a pair of 7.5cm infantry guns must have offered something the mortars couldn't supply.



I'll readily admit that mortars are not capable to replace the I.G. in every role 100%. 
An 'intermediate' I.G. of maybe 105mm calibre, fitted with muzzle brake, weighting circa 700-800 kg would've been maybe the better solution than going for 7,5cm + 15cm combo; nice punch, yet far less demanding on 'dedicated' prime movers.


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## psteel (May 13, 2012)

The guy doesn't understand so no point in wasting any more time on him.


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## davebender (May 13, 2012)

> ntermediate' I.G. of maybe 105mm calibre, fitted with muzzle brake, weighting circa 700-800 kg would've been maybe the better solution than going for 7,5cm + 15cm combo


Germany began developing the 7.5cm LG40 recoilless rifle during 1937. This weapon entered service during 1941 with a total of 450 produced. During 1942 Germany fielded the 10.5cm LG42 recoilless rifle. These weapons would have replaced existing German direct fire infantry guns but they were overtaken by new technology. Lightweight and dirt cheap Panzerfaust and Panzerschreck began entering service during 1943. These direct fire infantry weapons have nothing to do with mortars which are indirect fire weapons. Different type weapons for different missions. 

Large mortars such as the Soviet M1938 overlap with light howitzers to some extent. I'm attempting to determine the extent to which mortars can substitute for howitzers.


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## tomo pauk (May 13, 2012)

The 7,5cm LG40 was able to elevate at 42 deg, range being twice of the 7,5cm IG - hence, it's an artillery piece, able to do both direct and indirect fire. Ditto for the 10,5cm LG.


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## davebender (May 13, 2012)

Only if equipped with proper sights for indirect fire, which I doubt for a recoilless rifle or any other direct fire infantry gun.


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## tomo pauk (May 13, 2012)

Sure enough, proper sights are needed; even the Maxim MGs were sometimes having those. 
But, why you keep putting the German RR into direct fire artillery?


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## Shortround6 (May 14, 2012)

The German recoil-less rifles make good sense as specialized support guns for certain types of infantry like mountain and airborne. They don't make much sense as general issue direct fire guns. The regular German infantry guns _could _fire direct but were often used for indirect fire. Which is why they had zone charges. Recoil-less rifles used in the direct fire mode don't last very long unless they use their light weight to move early and often. This means frequent interruptions in their ability to provide support. Recoiless rifles have a very large firing signature and are hard to hide. They also cannot be used from bunkers or inside buildings. The German recoil-less guns also had a rather low muzzle velocity which, hollow charge shells and all, made them a bit short ranged for good anti-tank work, especially considering they weren't going to get many repeat shots. 

The Russians were able to use large mortars and get away with it for a number of reasons. Also remember the qualifier "get away with it".

The Russian use of large mortars _AS_ substitute artillery came about for a number of reasons. Lack of real artillery being one. Mortars being cheap is another. But you have to look at other things going on. Russian tactics were often simple. Russian communications between units was not good, shortage of radios, field phones and phone wire. Russian unit sizes were often smaller than German units of the same "name". A German Regiment could be much larger than a Russian Regiment and so on. The Russians also had artillery battalions, regiments and divisions that were not _ALL_ integrated into parent units like most western armies. A Russian Brigade or Division could seem to lacking much artillery on it's "paper" TOE but could have separate artillery units attached to it an a temporary basis or in some cases not "attached" to it but firing in support of it at the direction of higher command. The Russians even organized (later in the war) artillery corp and perhaps an artillery army or two (?) to support certain operations or offensives. 
What this means is that while the Russians may have used 12cm mortars as regimental or divisional artillery they were still building, issuing, and using conventional howitzers and guns in large numbers to support them.


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## davebender (May 14, 2012)

1935 Germany had the same issues only worse. They had to equip 36 army divisions almost from scratch. OHL would have known about French and Finnish 120mm mortars so they must have considered a 120mm mortar of their own.


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## Shortround6 (May 14, 2012)

The Difference is that the Soviets didn't intend for the mortars to be a total substitute for regular artillery. A German division was expected to operate more on it's own and require less support from Corp or Army. The Russian units were not expected to either cover the frontage as the German units and were given more high level support. 
Equipping Divisions in peace time with substandard weapons leaves you nowhere to go when the war breaks out. The 120mm mortar is not a substitute for the 105 howitzer.


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## davebender (May 14, 2012)

I agree but 120mm mortars available within 6 months are better then 105mm howitzers available three years from now. Nor would heavy mortars become useless when howitzers finally arrive. They could be grouped into heavy mortar battalions which provide additional punch for offensive operations.


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## tomo pauk (May 14, 2012)

On one-to-one basis, 120mm mortar is indeed not an substitute for the 105mm howitzer, ww2 time frame. Substituting 1 howitzer with 3 mortars maybe works better? Or the Germans should went for something in 14-16 mm calibre, to substitute both 105mm how and 15cm sig? 

It is rather significant, though, that Germans copied Soviet mortar and issued it to their units - a signal that it was providing them with one or more features that were absent from their weapons. The absence of recoil system might be the one, allowing the operation when General Winter took charge?

The 120mm mortars and heavier were considered as artillery weapons in ex-Yu army, while 82mm and lighter were considered as infantry weapons. Perhaps based on Soviet doctrine, ex-Yu army being influenced in many things by Soviet army?


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## davebender (May 14, 2012)

The German Army was still absent a whole lot of stuff as of June 1941. It's possible 120mm mortars were already on the procurement wish list along with 105mm SP howitzers, 17cm long range heavy artillery, towing tractors, 4WD Opel Blitz trucks, a 32 ton MBT, enough Sd.Kfz.251 to completely equip all armored and mechanized infantry divisions, a new infantry rifle chambered for the 7.92 x 33mm cartridge adopted during 1940 etc.


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## psteel (May 14, 2012)

I was reading Hogg and another source and they pointed out that Recoilless rifles were a dead end for germany because they consummed far too much propellant, which was needed for larger amounts of heavy artillery. This is why they went to the 'High Low pressure gun' at the end of the war, because it was more in line with the amount of artillery consumption of propellant.

One of the main reasons germans went to mortars over Infantry guns later in the war, was the fact that most artillery that was lost was left behind and mortars would be much easier to transport as organic units of war.....that and the fact they were alot cheaper and easiler to mass produce.


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## Shortround6 (May 14, 2012)

tomo pauk said:


> On one-to-one basis, 120mm mortar is indeed not an substitute for the 105mm howitzer, ww2 time frame. Substituting 1 howitzer with 3 mortars maybe works better? Or the Germans should went for something in 14-16 mm calibre, to substitute both 105mm how and 15cm sig?
> 
> It is rather significant, though, that Germans copied Soviet mortar and issued it to their units - a signal that it was providing them with one or more features that were absent from their weapons. The absence of recoil system might be the one, allowing the operation when General Winter took charge?
> 
> The 120mm mortars and heavier were considered as artillery weapons in ex-Yu army, while 82mm and lighter were considered as infantry weapons. Perhaps based on Soviet doctrine, ex-Yu army being influenced in many things by Soviet army?



For an exercise try drawing out on a piece of paper a deployment for the guns. The 105s had traverse of 60 degrees, draw to scale and put the guns 6-8000meters behind the lines and play with spacing. 3000 or 6000 meters apart. See the overlap on the front line and support it can provide without moving in the advance and how far into enemy territory it can shoot hit enemy mortars and artillery. 
Now try siting mortars with 6000meters range. See how much smaller the area they can cover or how many more you need. 

For an Idea of what the Germans tried to achieve with the 120mm mortars see.

http://www.wwiivehicles.com/germany...tion-and-equipment/1939-infantry-division.png

http://www.wwiivehicles.com/germany...tion-and-equipment/1944-infantry-division.png

See the levels at which the 120mm mortars were attached (in the inf battalion), and see the reduction in numbers. 1944 Division was about 2/3 the size of the 1939 Division. 

Find TOEs for soviet units and see where and how they used 120mm mortars.


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## davebender (May 14, 2012)

> Recoilless rifles were a dead end for germany because they consummed far too much propellant


I've read that opinion also but I don't believe it.

Inexpensive LAWs have largely replaced recoilless rifles in most armies. 1943 Germany was at the forefront of that shift with the Panzerfaust. Without the Panzerfaust (and Panzerschreck) I think the Heer would have continued to develop and procure recoilless rifles. Eventually they would end up with something similiar to the Carl Gustav which historically entered Swedish service during 1948.


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## davebender (May 14, 2012)

I doubt 1935 Germany had enough offensive capability to advance into Luxemboug.

If Germany procures mortars during the mid 1930s they would be strictly for defensive firepower to stop a French or Polish invasion.


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## Shortround6 (May 14, 2012)

You are assuming that a 1931-33 mortar has the same performance as a 1940-42 mortar. 

You are assuming that the Germans were defensive minded in 1935.

You are assuming you can train for offensive maneuvers using defensive weapons. 

Please look at the TOEs again. German divisions shrunk because of manpower shortages and the desire for more if less powerful units. The Germans used the 120mm mortars to beef up the infantry battalion as the Divisional artillery pretty much stayed the same at sixteen 4 gun batteries. Please note that the the number of batteries did not shrink (on paper) and that the 12cm mortars were not supposed to be used in the divisional artillery regiment/battalions. The ratio of artillery and mortar tubes per 100 men increased. Germans used "liberated guns" from Czechoslovakia, Poland, France, England and Russia to equip Divisions with rather than standardize on a cheap mortar despite the simplified logistics the mortar might bring with it. Feeding the guns was a problem in it self. A 1939 German Infantry division carried up to 230 tons of artillery ammo. keeping 4 somewhat centralized battalions supplied is one thing. trying to keep more mortar tubes, spread out in more locations and closer to the front line supplied is another thing. 

the 12cm mortar is a good weapon but it is not a 105mm howitzer and all the wishing in the world won't make it one, no matter how cheap it is. having a good mix of expensive capable weapons and less expensive weapons is a good idea, focusing too much on price leads to having too many weapons that don't have the capability to do what needs to be done.
All the countries that built tanks and tankettes by the hundreds in the 30s. Are 100 tankettes worth even twenty 15 ton tanks? 
The RAF with those thousands of Blenheims and Battles. A bomber force large in numbers (good for training) but really lacking in the ability to penetrate enemy airspace and carry a worthwhile bomb load. How many Battles equal one Whitley?
The list goes on. Sub chasers that are slower than the subs they are chasing (and have less armament). Most anti-tank rifles, certainly cheap compared to even a 37mm AT gun. but effective after 1939-40? or even in 1940?


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## psteel (May 16, 2012)

davebender said:


> I've read that opinion also but I don't believe it.
> 
> Inexpensive LAWs have largely replaced recoilless rifles in most armies. 1943 Germany was at the forefront of that shift with the Panzerfaust. Without the Panzerfaust (and Panzerschreck) I think the Heer would have continued to develop and procure recoilless rifles. Eventually they would end up with something similiar to the Carl Gustav which historically entered Swedish service during 1948.



Ian Hogg....pp249 "German Artillery of WW-II"



> In other words it took three times as much propellant to push a shell from a recoilless gun as it did to achieve the same velocity from a conventional gun"



According to the USSBS by 1943/44 , Germany had increasing problems building sufficent ammo due to lack of propellant chemicals factories that were being bombed relentlessly by the allies.

BTW Laws etc are rockets and are launch using a different mechanism.


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## starling (May 24, 2012)

After all ,it was the Germans who had too many differing weapons,calibres etc,and the Russians must of been doing something right,because they won the war,with some help from their friends.this is a general assumption of course.


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## tomo pauk (May 24, 2012)

Connecting the bigger number of the different calibers Germans fielded with their defeat is an oversimplification. Trying to win a war against 4 major forces is not something one should attempt.


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## starling (May 28, 2012)

But they did,and lost.


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## davebender (May 28, 2012)

Not all of them. The Panzerfaust was a recoilless gun with the black powder propellent burned inside the launch tube.


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