German 7.9mm ammo for Luftwaffe WB 81 Weapons Pod


#1

In 1944-1945 Metallwarenfabrik Treuenbrietzen, Selterhof (hlb) made ammunition especially for use in the WB 81 weapons pods which contained six (three MG 81Z dual) guns. The firing rate of these guns was 1700-1800 RPM per barrel or 10,200-10,800 RPM for the Pod. The Junker JU-88 and Dornier Do-217 had the capability to carry six WB 81 weapons pods so for a short period could fire at a 61,200-64,800 RPM rate!! It’s no wonder they were nicknamed “watering cans”.

Feeding problems were encountered because of bullets becoming loose in the cases and jamming the disintegrating cartridge belts in the chutes. This was solved by adding an additional bullet crimp to the necks of the cases.

fer (Metallwerke Wandhofen GmbH, Schwerte/Ruhr, Rosenweg, bei Dortmund) cases dated 1943-1944 can also be found with a additional crimp on the case necks but these shouldn’t have been for use in the Luftwaffe WB 81 weapons pods, since the Air Force would only accept Zdh. 88 (and for a short time Zdh. 43) primers. All the fer cases with the extra crimp I’ve seen have Zdh. 30/40 primers.

Now for the purpose of my post. The only labels for these rounds I have seen are for SmE 15 round boxes and they have no indication that they are anything other than normal rounds. Does anyone have a 300 round sleeve or 900/1500 round case label or an auxiliary label that indicates WB 81 use only?

Also does anyone have a box label for the SmK and SmK L’spur loadings with the extra neck crimp?




#2

Do you have any documentation confirming that it was actually made for the WB-81 pod? Cartridges with additional neck crimp are found in s.S., S.m.E., S.m.K., S.m.K.-L’spur, P.m.K., P.m.K.n.A. and B-Patrone, but first two seems to be pretty odd for aviation use. A laquered case specimen also exists and doesn’t seem to fit aviation use.

You can download WB-81 manual here:
sendspace.com/file/wh4ep2


#3

My sources for the hlb S.m.E. loading with dual crimps being used in The WB 81 weapons pod are “German 7.9mm Military Ammunition” by Daniel Kent page 55 and “Die Patronen 7,9mm der Deutschen Wehrmacht 1930-1945” by Windisch/Micke/Kellner page 25 of the English translation.

Whether or not the examples shown in my post were actually made for the WB 81 Pod was what I was attempting to determine with my questions.

Although it is mentioned in German military documents, a specimen of the P.m.K.n.a. loading has never been discovered to my knowledge, such as it is.

Thanks for the link but I have a copy of the manual.


#4

Apparently the SmE loading was used in aircraft MGs (including the MG81). Here is an excerpt from a Luftwaffe manual.

Does anybody know what manual this excerpt was taken from? I neglected to write it down when I copied it.


#5

Sorry for confusing the issue. When I said “pretty odd for aviation use” I was thinking of fixed MG17 machine guns and not flexible MG 15, 17 & 81.

A German collector claim to have a PmKnA round headstamped hlb S* 4 44. I cannot confirm his correct identification so you may be right about it.

That excerpt was taken from “Munitionsvorschrift für Fliegerbordwaffen Teil 10 Handbuch der Munition für Fliegerbordwaffen”. You have a late edition (1944?) showing SmE, SmE L’spur 100/600, SmE Gl’spur and PmKnA. There’s another one dated June, 1942 showing some differences:


#6

Fede – thanks for identifying the manual that excerpt was taken from. I will have to do some web searching and see if I can download a complete copy.


#7

Do you already have June 1942 edition?


#8

No, I only have the part I posted and the drawings of the P.m.K.n.a and S.m.E. L’spur.


#9

I’ll send you a copy.


#10

The pod was made for an anti personal rule and against vehicles and trucks.
It is not an anti tank or airfight weapon. So ball ammo is quite useful.
At least for training the crews.

As far as I know the loosening and popping out of bullets was a MG 81 problem - not a pod problem. I have a report dealing with this somewhere. They made trials in Rechlin and the additional crimp was the easiest way for success.

The MG 81 was used in ground combat too. It was used by the navy for AA combat. From mid 1943 a lot where delivered to the sub fleet and installed at the conning towers. May be the steel case and 30/40 primed ammo was made for this none aircraft use. Steel cases for the 2cm and 37mm ammo was common at navy use in 1943.

I will look for the report.


#11

This is a copy from a report from E’Stelle Rechlin from June 1th 1943 about a test, 7.9 Mauser cartridges in the MG81.

On the first side of this report is written in German that it was not successful with B-Patrone.
By pressing of the case with an additional crimp the B-bullet was damaged.
For the test they loaded a small quantity of sS, SmK, SmK Lsp 100/600 and PmK The test was taking place with a 60 and 80°C environment temperature.

They did not order SmE and SmK Glimspur, because they were the same as sS and SmK Lsp.
Because the rounds with an additional crimp give a pressure over 3500 at (I don’t know how many Pound inch² it is) it was necessarily to reduce the powder load to 2.8 gram.

The time using 7,9 rounds in airplanes was over at the end of 43. The armor from allied plains was too strong. They start using 13, 15, 20 and 30mm machine guns. The MG 81 was reworked for ground use.

The cartridges for this test were made by Polte. Unfortunately I have never seen one of this company with this additional crimp.

I know of SmE, SmK and SmK Lsp all made by “hlb”

sS, PmK, PmK nA and B-Patronen with an additional crimp are unknown to me.



#12

Dutch and genkideskan – Thanks a lot for the additional information.


#13

Assuming that one atmosphere is equivalent to 14.7 lb./sq. ft., then 3500 at should represent about 51,500 lb./sq. in., a relatively high chamber pressure. Jack


#14

[quote]fer (Metallwerke Wandhofen GmbH, Schwerte/Ruhr, Rosenweg, bei Dortmund) cases dated 1943-1944 can also be found with a additional crimp on the case necks but these shouldn’t have been for use in the Luftwaffe WB 81 weapons pods, since the Air Force would only accept Zdh. 88 (and for a short time Zdh. 43) primers. All the fer cases with the extra crimp I’ve seen have Zdh. 30/40 primers.[/quote]

I only have one ‘fer’ fired case so i’ve nothing to compare with, and was wondering if this is an example of above, and if not for the WB 81, was there any other reason for the additional crimp?

Thanks


#15

I have or have records of the following fer cases with the extra neck crimp:

fer S* 9 43 sS steel primer – Zdh. 30/40 (have)
fer S* 10 43 sS steel primer – Zdh. 30/40 (have)
fer S* 11 43 sS steel primer – Zdh. 30/40 (have)
fer S* 11 43 SmE steel primer – Zdh. 30/40 (have)
fer S* 12 43 sS steel primer – Zdh. 30/40 (have)
fer St+ 5 44 SmE lac. steel case, steel primer – Zdh. 30/40
fer St+ 7 44 SmE lac. steel case, steel primer – Zdh. 30/40
fer St+ 8 44 SmE lac. steel case, steel primer – Zdh. 30/40

The reason for the extra crimp on these cases is up for debate as far as I know

The box pictured contains a mixture of fer case lots 9 and 12 of 1943 which is not unusual for boxes from 1943 and later.


#16

The fer steel cases are not made with an extra neck crimp.
It was a error in the crimping machine.
The neck crimps on the fer steel cases are different in hight and depth by every lot number.
They discovered the problem I think by lot number 8/44

451kr.


#17

Fede was kind enough to send me a copy of the 1942 edition of “Munitionsvorschrift für Fliegerbordwaffen Teil 10 Handbuch der Munition für Fliegerbordwaffen” he and pbutler mentioned earlier. This pbulication includes ammunition from .22 to 30mm.

I have posted it as a Free Download on my website at http//:gigconceptsinc.com. Select the “Free Downloads” button on the left side which will take you to the full list of free downloads of ammunition related information.

Cheers,

Lew


#18

Thanks Lew

regards
Harrie


#19

Even though not my field,the Free down load is great,
many thanks
Charles.J.Wells (Jack)
Sgm. USA. Ret.


#20

451k

Thanks for the information about the steel cases. I have never seen a specimen or a picture of one. I was going by what had been reported to me. What seems a little bit strange to me is if they didn’t correct the error with the crimping machines until lot 8, several million rounds could have been loaded and it looks like they should be more common. Maybe they are in Europe. This is assuming fer actually loaded the cases. Of course there are many lot numbers that don’t seem to have survived the war so one type not being common is no surprise. Does anyone have an example they can post a picture of? I would like to see one.