Interesting shell/armament developpments in 1938/1940

[David Lehmann]

In 1938/1940 several companies like for example the French company Brandt initiated different interesting technical developpments in the field of shells and armament ... several examples :

- Brandt 120 mm mortar Mle 1935 :
This heavy mortar had been adopted by the French Army and a squad of 2 mortars should have been issued in each regiment in 1940 but only few had been delivered before the armistice. This mortar was also manufactured in Russia under the name "120mm Polkovoy Minomyot Obr.1938g". The Russians used it extensively (that's why it is often thought that this mortar is a russian conception) and it has later been copied by the germans for their "120 mm Granatewerfer 1942".

- Brandt 25 mm AT shell and taper-bore AT guns developped for the French army :
The 25x194R shell used in the 25 mm Puteaux Mle 37 APX and 25 mm Hotchkiss Mle 34 AT guns was taken as the basis for the taper-bore experiments conducted in 1940 by the Danish Larsen company for the French Army. Larsen developped a 29/20 mm AT guns that should have replaced all the French 25 mm AT guns. The 29/20 mm shell is manufactured by the French company Manhurin. These studies were then followed up by the Germans to create different Gerlich type taper-bore AT guns : 2.8 cm sPzB 41, 4.2 cm lePak 41 and 7,5 cm Pak 41. They worked very well, but suffered from a shortage of the tungsten needed in the projectile.

- New generation shells :
The studies led by Brandt in 1938/1940 aimed to increase the initial velocity of the shells (without increasing of the chamber pressure) and also more generally to increase the AT power of the shells. The French company developped a serie of sub-calibrated shells for the 25, 37, 75, 155 and 203 mm calibers (the two last ones for the French navy). The other nations did not developp similar or equivalent systems before 1941/1942. The most outstanding realization of this serie is probably the 75/57 mm shell with a muzzle velocity of 900 m/s and a penetration of 90 mm armor at 1000 m at an impact angle of 35° ... The 75 mm Mle 1897 guns could have engaged and destroyed german Panzer IVs at 2500 m with it ! But with the standard 1910M "breaking" shell the panzers were generally engaged/destroyed at 600 m.
Except the sub-calibrated shells, Brandt also developped a 75 mm HEAT shell at this time, using the patent of the swiss Mohaupt. The tests took place in Bourges in 1940 and the results were that impressive that they were put in the secret immediately.
The war ministry allowed Brandt to give the exploitation licenses to the USA and the United Kingdom. The sub-calibrated shells are used in th UK to developp the APDS shells (armoured piercing discarted sabot) issued from 1942/1943. The firts AT guns using them were the 6 Pdr and 17 Pdr AT guns.

example with the 6 Pdr AT gun (57 mm) :
AP shell : 821 m/s and 74 mm penetration at 1000 m
APCBC shell : 846 m/s and 88 mm penetration at 1000 m
APCR shell : 1075 m/s and 90 mm penetration at 1000 m
APDS shell : 1234 m/s and 146 mm penetration at 1000 m

example with the 17 Pdr AT gun (76 mm) :
AP shell : 883 m/s and 109 mm penetration at 1000 m
APC shell : 883 m/s and 188 mm penetration at 1000 m
APDS shell : 1204 m/s and 231 mm penetration at 1000 m

Notes:
AP (armour piercing)
APDS (armour piercing discarding sabot)
APC (armour piercing capped)
APCBC (armour piercing capped ballistic cap)
APCR (armour piercing composite rigid, tungsten corded)
Penetration figures are given at 30° angle of impact against homogeneous plate.

David

[daveh]

The basic idea for a tapered bore weapon with a flanged projectile to increase muzzle velocity dates from a 1909 patent. Gerlich worked on this idea years before WW2 started. The idea was used in sporting rifles initially. Gerlich worked with both the Americans and the British looking at high velocity rifles based on tepered bores. None of these experiments were successful and he returned to Germany where he worked on tapered bore AT guns at Krupps. The first, the 2.8cm schwere panzerbusche 41 was approved for service in November 1940.

Given the work of Gerlich in this field pre WW2 and the approval of the 2.8cm design in November 1940 I wonder how much impact the Brandt/Larsen work work had on the Germans. Did it confirm the ideas that Krupp/Gerlich were presumambly working on? or did it lead to a new approach? or an acceleration of the work?

I would be very interested in your comments.

Was the Brandt 120mm mortar mle 35 offered to the Soviets for licenced production? Was any other french equipment offered for sale/ licenced production to the soviets? and was any taken up?

As always the information you provide is of great interest. It also makes us consider our perception of the French Armed Forces and arms industry as ineffective and backward in comparison to other nations in 1939-1940.

Do you know, or anyone else, know of the developments of the French aircraft industry of this period. I have seen W. Green's books on Aircraft of WW2 which includes a wide range of new designs being developed in 1939/40.

[David Lehmann]

Hi,

Well I have no details about the Danish/French (Larsen/Brandt) cooperation about the tapered bore guns ... I only know the French 25 mm AT shell has been used as basis. I cannot really affirm that it had significant impact on German developpment and I do not know the main advances these researches lead to ... that's not precised in the books I have ... it simply says that it had an impact on further developpments, so I think there should have developped some technical improvements. In fact these experiments were succesful in opposition with Gerlich first onces. I have no more details sorry.

About the russian I do not really know if there were other equipments produced under French license ... I was just amazed when I discovered that the russian 120 mm mortar was in fact exactly the French Brandt mortar (In Stéphane Ferrard's book : France 1940, l'armement terrestre).

Thinking that French armaments were worse than the others is totally false ... the doctrine, the high command and the communications were bad but not the equipment.

About the Aircrafts some really modern fighters for example like the Dewoitine D.551 and the Arsenal VG.33 had been developped but arrived to late to enter the war. The best fighter was the Dewoitine D.520. But the main fighters that had to deal with the Luftwaffe were Morane Saulnier MS.406, Bloch MB.152 and american imported Curtiss Hawk 75 that were really not as good as the Me109. Nevertheless the Me109 was the german plane that had been the most shot down.

David

[daveh]

Many thanks David.

The fact that the soviet 120 mm mortar was a French design was certainly a surprise!!

I think that the French tapered bore work probably helped confirm the German work adding some possible lines of improvement i.e. a definate help but not vital.

You mentioned that

the doctrine, the high command and the communications were bad

I know something of the first two but for the last do you mean at divisional level or at high command level? or both? I know of the use of phnoe lines rather than radio in many cases at the hihest command levels but have limited infromation on eg the distribution of radio equipment at the level of army and below.

The radio equipment itself is detailed at

http://france1940.free.fr/armee/radios.html

I look forward to more of your work on the French Armed Forces.

Thanks in advance.

[David Lehmann]

Yes in fact I just meant the lack of radio equipments but during these period even German panzers were not all equiped with radios.
The emetter/receiver equipments were at least as big as a fridge and weigted at least around the 50 kg that's why many tanks except command vehicles had only receiver equipments.

David

[David Lehmann]

At the end of 1939 Brandt developped a 50mm HEAT rifle grenade. It had a range of about 100m and an armor penetration of 40mm. It entered in production during May 1940 and was successfully tested at the Satory test range on 10th June 1940 but they could not be issued to the combat units before the armistice.
The patents were sent to the USA in June/July 1940 and were used first to developp the M9 AT rifle grenade and second the HEAT rocket of the Bazookas.
The Brandt HEAT rifle grenade was also secretely produced in France at 300000 pieces in the free area and issued to Vichy forces. Several partisans groups used them in 1944.

Regards,

David