120mm mortar - which country developed it?

[Juardis]

Reading Gavins book "On To Berlin" and he's talking about the drop into Sicily and says the Germans were using Russian 120mm mortars. What's up with that? Did the Germans capture the mortars for use themselves? Capture the plant that made the mortars? Steal the design and make them themselves? What?

[ 05-08-2001: Message edited by: Juardis ]

[WWB]

When the Germans invaded Russia they found out about some very superior Red Army weapons systems, mainly the T-34 and the 120mm mortar. The T-34 begat the panther, but the 120mm was just copied and put into service.

WWB

[offtaskagain]

<BLOCKQUOTE>quote:</font><HR>Originally posted by wwb_99:

When the Germans invaded Russia they found out about some very superior Red Army weapons systems, mainly the T-34 and the 120mm mortar. The T-34 begat the panther, but the 120mm was just copied and put into service.

WWB<HR></BLOCKQUOTE>

I've heard they used the same factory they captured from the Russians to make the 120mm mortars initially.

[Stalins Organ]

Actually the 120mm mortar (and 81/82mm) are often called "Brandt" mortars.

IIRC the guy was a Frenchman who perfected the basic design (or at least sold it to the French first).

[Michael Emrys]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Mike the bike:

Actually the 120mm mortar (and 81/82mm) are often called "Brandt" mortars.

IIRC the guy was a Frenchman who perfected the basic design (or at least sold it to the French first).<HR></BLOCKQUOTE>

I've never heard that name applied to the 120mm. I could be mistaken, but I believe the USSR developed it independently. The Germans adopted it after noticing what a useful weapon it was. I think they did some detail design modifications on the carriage to adapt it for their use. I haven't heard of it being manufactured in captured factories which I suspect the Soviets would have left in u/s condition anyway.

Michael

[JasonC]

"the Germans were using Russian 120mm mortars. What's up with that?"

The Germans copied the 120mm from the Russians, and made around 8500 of them themselves. They also captured a number of them and used them, but how many I don't know. The Germans used captured ammunition and also produce 5.4 million 120mm mortar rounds themselves. The German produced 120mm mortar was called the 12 cm Granatwerfer 42. Captured Russian ones in German service were designated the 12 cm Granatwerfer 378®.

The numbers can be compared with 79,000 81mm mortars and 26,000 50mm ones in the early war, with 74 million 81mm rounds made and 22 million 50mm rounds. The 81mm mortar was by far the most common type in German service from mid-war on. It was used at company and battalion levels. The 120mm mortar was used at the regimental level in place of infantry guns. It seems to have been especially common in SS units in the late war, probably because they were more likely to be at full TOE in all weapons.

The timing of German mortar ammo production is also interesting. Large numbers of 50mm rounds were made in 1940. Far lower numbers of mortar rounds of all types were made in 1941 and 1942. In 1943 and 1944, large numbers of 81mm mortar rounds were produced.

This probably reflect large stocks of captured ammo available in 1941 and 1942, as well as phasing out the 50mm mortar, and a continued reliance on infantry guns. In the later defensive period of the war, 81mm mortars were more heavily used and ammo for them had to be made in Germany, rather than captured.

The Russians made around 47,000 120mm mortars over the course of the entire war. Most were produced in 1942 and 1943. They made 152,000 82mm mortars, and in the early war 145,000 50mm ones. Russian practice in the early war was to use 50mm mortars at the company level, 82mm at battalion level, and 120mm mortars at regimental level. They soon found the 50mm lacked sufficient punch and replaced those with 82mm mortars as well.

The much higher portion of 120mm mortars made by the Russians, compared to the Germans, primarily reflects the fact that Germans continued to use infantry guns for additional infantry firepower - 75mm and 150mm SiG. Similarly, the U.S. used cannon companies of 105mm pack howitzers at the regimental level. Essentially the same role was fufilled in the Russian army by abundant 120mm mortars.

The Russians produced enourmous numbers of mortar rounds during the war, though the breakdown by type I haven't found yet. All told, they made 251 million mortar rounds, ramping in 1942 and leveling off at ~75 million rounds per year in 1943-44. By then they had phased out the 50mm mortar, so those were heavier 82mm and 120mm shells.

How many 120mm mortars did the Germans capture? I haven't seen a figure so it is hard to say anything definite, but some reasoning can be supplied. The Russians had relatively few 120mm mortars in 1941. Their common use increased over the course of the war, and most of the weapons used were made in 1942 and 1943. Nearly the whole 1941 production was probably subject to capture, though many were probably destroyed instead. Only a portion of the 1942 production can have been captured, as the Germans advanced a long way only in the south, did most of that advancing before many of them would have been made, etc.

This sort of reasoning suggests the number captured was probably in the thousands, somewhere between half the German-built number and equal to it (i.e. 4250-8500). So the total 120mm mortars available to the Germans may have been around 15,000, plus or minus 2000 or so, with 1/3 to 1/2 of them a Russian-made weapon. The lower end of that range may be more likely.

Deducting their early losses, the Russians may have had ~35000 available, roughly half of them by the begining of 1943 and the other half by the begining of 1944. Mortar tube production in the last year and a half was low, replacement rate or less. Mortar ammo production remained very high. They probably had all the tubes they could feed by the begining of 1944. Mortar tubes are very cheap to produce, and they can fire off ammo rapidly, making the ammo production the real constraint.

I hope this helps, and the detail is interesting to at least one grog - LOL.

[jshandorf]

12cm - Granatwerfer

After germany attacked russia in 1941, they encountered the large russian PM 38 12cm mortars. Not only were any captured weapons immediately used in german service under the designation 12cm Granatwerfer 378®, the germans were so impressed by this weapon that they immediately prepared to produce their own copies. This design was called 12cm Granatwerfer 42. The tube had a length of 186.5cm and the complete weapon weighed 285kg. It fired the Wurfgranate 42 that had a length of 72.1cm and weighed 15.8kg incl. 3.1kg of explosives. The warhead was usually fitted with the Abstandszünder 41 ("distance detonator") extender fuse. With a Vo of 283 the maximum range was slightly over 6km. The weapon proved a very successful design, total production (1943-1945) was 8,461 12cm Gr.W.42; it was comparably cheap and cost the germans 1,200.- RM apiece to produce. Of it's ammunition, the Wurfgranate 42, a total of 5,373,000 was built from 1943 - 1945.

[JasonC]

"often called "Brandt" mortars."

A misunderstanding. The Brandt mortar was an interwar design by a French company of that name, their model 27/31. It was the mortar that standardized caliber at 81mm (3.2 inch), and was bought by most armies, except the UK. The Russians made a copy themselves, the 82mm, which was 1mm larger in caliber to enable them to use captured ammo but not the reverse.

But the Brandt was not the original. That was the Stokes 3" mortar of WW I, invented in 1915 by F. William Stokes, a British engineer. The Brandt was a copy of its principles, in a slightly larger caliber.

And there were a great variety of mortars before the Stokes or alongside it. The Stokes principle is still the one used in all later mortar types, in the following sense: a fixed firing pin at the base of the tube, whole projectile goes down the tube, smoothbore, medium caliber, fin-stabilized rocket, achieving a high rate of fire and reliable performance.

In WW I, there were heavier mortars of many types without a fixed firing pin, set off by lanyard from as far as 15 meters away (because they were dangerous). They were glorified stumpy howitzers, in effect, with calibers up to 240mm. There were also types with the bomb staying outside the tube, only a rod going into it, with seperately loading powder charges behind the projectile - so-called "spigot" mortars. Some in light, grenade-launcher caliber. Some in medium, and some huge bombs ("flying pigs" they were called) on the end of the rod. Before that, the UK used "Garlands", which fired a grenade made out of an empty jam tin through a hollow tube with a propellant charge of bags of black powder. And much larger, iron-shell mortars date back to the 18th century - they were used in the US civil war, in the war of 1812, etc - especially as seige weapons or high-angle naval guns for bombardments.

The modern mortars stem from Stokes 3" of 1915, which incidentally the Germans captured in a trench raid in 1916. "Stokes-Brandt" was used in the interwar period to refer to any weapon on the same principles, after the adoption of the Brandt 81mm caliber as standard. But Brandt did not invent the modern mortar, and the Russians were the ones to come up with a 120mm caliber version.

[gunnergoz]

<BLOCKQUOTE>quote:</font><HR>Originally posted by JasonC:

[QB...whole projectile goes down the tube, smoothbore, medium caliber, fin-stabilized rocket...[/QB]<HR></BLOCKQUOTE>

Jason, isn't it fair to say that a "rocket" continues to burn propellant past the point it leaves the laucher? A mortar round consumes all the propellant charge within the tube and depends upon the expanding gases in the tube to provide the thrust for the projectile.

I would find it hard to agree that a mortar is a "rocket" in any sense.

[Panzer_Meyer]

Thanx Jason,

A very interesting post, both of them!

[Stalins Organ]

Thanks everyone for hte info and clarifications - great stuff!!

One point tho' - I agree with Gunneroz that the mortar "bomb" is not a rocket.

A rocket has the propellant internal to the projectile, whether it continues to burn outside the tube or not (eg Bazooka and Pz-faust rockets do not burn outside the tube).

[grunto2]

<BLOCKQUOTE>quote:</font><HR>Originally posted by JasonC:

Far lower numbers of mortar rounds of all types were made in 1941 and 1942. In 1943 and 1944, large numbers of 81mm mortar rounds were produced.

This probably reflect large stocks of captured ammo available in 1941 and 1942...

<HR></BLOCKQUOTE>

wait a minute... where would the germans have captured the 81mm ammo? the russian equivalent was 82mm wasn't it?

it's my understanding that the german 81mm ammo would work in a russian 82mm tube but not the other way around.

is that right?

andy

[Guest Babra]

It would be nothing at all to machine 1mm off a mortar round. Far more sophisticated remachining was being undertaken with tank ammunition in Africa, far from any manufacturing facilities.

[Stalins Organ]

The Germans also captured thousands of 82mm mortars to use the ammo in!!

Also they had captured a lot of 81mm ammo in France and otehr countries that used teh 81mm mortar.

Babra what are you referring to about ammo being machined in Africa?

[Guest Babra]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Mike the bike:

Babra what are you referring to about ammo being machined in Africa?<HR></BLOCKQUOTE>

It's late and I'm tired. Don't make me look it up... I'll post it later in the week if someone hasn't first.

[Michael Dorosh]

Russian mortars WERE 81mm, were they not? And merely named 82mm for logistical purposes?

[Michael Dorosh]

Acutally, I may be confusing another piece of German or Russian ordnance - there was something used in WW II that was given a different mm size solely for logistical reasons.

Incidentally, one source I just checked talks about rocket assist on 120 mm mortar bombs....

[Michael Dorosh]

How's this for pompous? Three posts in a row.

"The principal area of development has been to seek increased range...The method most generally adopted is to add rocket assistance to the bomb. An example of this is the 120-mm bomb offered by the French Hotchkiss-Brandt concern. This bomb is of conventional form but has a rocket motor fitted axially...."

This is, I am sure, a very recent development.

[JasonC]

"where would the germans have captured the 81mm ammo?"

France. Plenty of minor places. And as others have mentioned, they used captured Russian mortars as well as captured Russian mortar shells.

[JasonC]

"there was something used in WW II that was given a different mm size solely for logistical reasons."

That is possible, but the ordinary case is when two weapons have the same caliber but different ammo. The only such case I am aware of is the 106mm recoilless rifle, the post-war weapon in U.S. service and I think other NATO countries as well. It was actually a 105mm piece. But they just called it a 106mm piece, so that QM types would not send howitzer shells where rocket rounds were wanted, and vice versa.

If the Russians used "82" for the same reason, then the question would be, to distinguish it from what? I don't think they used another weapon of 81mm caliber. They did use 82mm multiple rocket launchers as well as mortars, but both had the same caliber designation - 82.

[argie]

I just read that Russians used the 82mm barrel to let him use another countries ammo (81mm) meanwhile avoiding the use of his captured ammo for the others... At least without machinery...

I think the 77mm gun in the British Challenger was another case on naming a gun with a caliber different to his own (76mm).

Also I remember something about 122mm Soviet ammo, but I'm not sure where I read it and what logistical nightmare was this preventing and in which timeframe

Very scientific approach, eh?

[Guest Babra]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Mike the bike:

Babra what are you referring to about ammo being machined in Africa?<HR></BLOCKQUOTE>

From Hunnicut's "Sherman":

<BLOCKQUOTE>quote:</font><HR>A successful effort to provide effective armor piercing rounds resulted from the brilliant idea of Major Northy, an Austrailian serving with the Royal Army Ordnance Corps. Early in 1942, about 50,000 tons of assorted German ammunition...were moved to the Ninth British Army Depot...Among this vast supply were many of the explosive-loaded APCBC rounds for the Panzer IV's 7.5 cm KwK L/24...<HR></BLOCKQUOTE>

Anyway, to make a long story short, about 17,000 rounds of this ammunition were machined and altered to fit the 75mm gun for the M3 Lee/Grant. The work was completed in two weeks and the ammo sent up in time for the Gazala battles.

If such a project could be undertaken in the field, I would think modifying mortar shells (if it was even necessary) would be a piece of cake.

[JasonC]

"A rocket has the propellant internal to the projectile, whether it continues to burn outside the tube or not"

Right. And I agree, mortars are not really rockets; I should not have said so, and I accept the correction.

The propelling charge is in the mortar round. It detonates when the firing pin at the base of the tube sets off its primer. It burns rapidly, and the explosive expansion of the gases from that detonation accelerate the rest of the round up the tube.

Improving the way that powder burns, slowing it to achieve a more even acceleration, and thus to allow a larger overall powder charge to be used without overstressing the tube, was a means of improving mortar range. There are some similarities, since the burning powder is being accelerated up the tube, but basically the principle is better thought of as the same as in ordinary artillery shells. All the powder burns in a confined space, the effective "chamber" size, just as in ordinary artillery.

Here is a little discussion of extending the range of the U.S. 4.2 inch mortar during the war -

"After troops tried out mortars in Europe, they began calling for a longer range. Back in the U.S., the CWS (Chemical service) had already anticipated the demand and had succeeded in adding another thousand yards to the flight of mortar shells. It had achieved the increase by changing the form of the propellant so that it burned slowly, gave off gas more evenly, and thereby became more efficient. Lt. Arthur Denues had experimented with the propellant, trying different shapes, arrangements and types, and had finally found out that with disks of powder of a certain thickness, the range depended upon the number of disks.

The minimum charge, which lobbed the shell only 340 yards, could be lengthened to 4400 yards simply by adding more disks. The maximum gas pressure did not become excessive and there was no disturbance in the ballistics of liquid-filled shells. The disks were cut square, with a hole in the center to allow the disk to slip on the cartridge container. Sufficient disks, sewn together in bundles of different thickness, were placed on each shell before shipment to give a range of 4397 yards. Before the shell was fired, the mortar squad could remove one or more disks to shorten the range."

That is basically like "cutting" the powder charge of a semi-seperate ammunition howitzer, like the U.S. 105mm.

[JasonC]

"I think the 77mm gun"

Yes, that is another good example. Several guns were designated "77mm" in this country or that, when in fact no weapon of that caliber was used, by anyone. It was a quarter-master's designation. But one does not find such a practice, unless their is something to confuse the renamed shell size with, a different type of the same caliber.

It is possible the 82mm was really the same size, since the original Brandt was 3.2 inches = 81.3mm. Maybe some rounded that down, and the Russians rounded it up. I've heard the story that they deliberately made them 1mm larger for the sake of the captured ammo difference, many times from many sources, but it is vaguely possible it could be a common but apocryphal story.

[ 05-09-2001: Message edited by: JasonC ]

[JasonC]

A little more detail on the variety of 81mm mortars and equivalents in German service, from the "Panzerfaust" site -

They had their own, main version, and a shorter one used in the paratroops. Then they used -

274® - the Russian 82mm

278/1 (f) - the French Brandt-Stokes 81mm

31 (p) - a Polish 81mm, training only

36 (t) - Czech "8cm" version

33 (o) - Austrian "8cm" version.

The had around 1/4 million captured rounds for the Czech ones. No figures for the others.

Ammo weights for these types vary slightly - 3.25kg (French), 3.3kg (Czech), 3.4kg (Russian), 3.5 kg (Austrian and German models). They didn't list a weight of shell for the Polish one.

There was probably many differences, but all of them tiny, between the types. The overall effectiveness of any of them would be much the same.