German 20mm projectile ?

[thehairbarebunch]

Hi Navyman,

Sorry for the delay in my response, but the following may be of some use to you.

Most German fuses had an alpha/numeric code. Nose fuses had either the prefix AZ (Aufschlagzunder or Kopfzunder) for direct action or or impact fuse. If the fuse had an S.D. element the prefix was usually ZZ or Z.Zerl (Zerlegerzunder). So if a shell has a ZZ stamp on the fuse Self Destruct will be initiated by the fuse and not from the tracer burn via a septum in the base of the projectile.

A couple of cutaway images of your 2cm M Geschoss MG151/20.

Regards

 

[Falcon]

Isn't it unusual that the round has a percussion primer?

All the other examples I have seen have electric primers.

 

[thehairbarebunch]

Hi Falcon,

The cutaway MGFF/MGFFM round in the images (and not an MG151/20 as I incorrectly stated. doh!) was fitted with a G.2 percussion primer. The MG151/20 could be either Electrically or Percussion primed.

 

[blackwatch]

Isn't it unusual that the round has a percussion primer?

All the other examples I have seen have electric primers.

No it is not unusual, We found only 20 mm with percussion primers,
on the german me 109,s the we have been excavate.

 

[thehairbarebunch]

The MGFF/FFM was fitted ONLY with the percussion primer, the 151 used both types depending on the aircrafts requirements.
Usually aircraft whose cannon were fitted with interuptor gear (FW190) used electric priming while those with cannon not firing through the propellor arc (Bf109G) used percussion.

 

[thehairbarebunch]

Hi Falcon,

By the way, how could you tell what primer was on the bottom of the cutaways ?

 

[blackwatch]

The MGFF/FFM was fitted ONLY with the percussion primer, the 151 used both types depending on the aircrafts requirements.
Usually aircraft whose cannon were fitted with interuptor gear (FW190) used electric priming while those with cannon not firing through the propellor arc (Bf109G) used percussion.

We found both (electric and percussion priming) on wing mounted,
mg 151.Another excavation group in my neighbourhood found once a FW 190,
with a mg131( with interuption gear)who fired rounds with percussion primers.
I can show you a picture of the case.

 

[navyman]

Hello Phil,
Thanks for the pics. What an excellent sectioned round.
best regards,
navyman.

 

[Falcon]

I was talking about the primer on Navyman's 20x82 Rimless round, he has shown a photo of the headstamp. There is no way I could have known what the primer on the cutaway was.

 

[Tony Williams]

We found both (electric and percussion priming) on wing mounted mg 151.

It was standard practice, for obvious safety reasons, to use only one type of MG 151 ammo on each aircraft (electric and percussion were hard to tell apart, so there was too big a risk of loading the wrong sort). So as the Fw 190 wing root MG 151 had to be electric primed (that was the way that the synchronisation system worked) that meant that all other MG 151 installed on Fw 190 had to be electric also.

Similarly, all MG 151 installed on Bf 109 were percussion-primed. There was a scheme to fit a gun in a belly pod, firing through the propeller disc. This worked very well (with far fewer performance and handling penalties than the underwing gun pods) but was abandoned because it would have required using electric-primed ammo.

Another excavation group in my neighbourhood found once a FW 190, with a mg131 ( with interuption gear)who fired rounds with percussion primers. I can show you a picture of the case.

I know that the MG 131 was developed in a percussion-primed version (it was sold to Japanese Navy in that form; they designated it 13mm Type 2) but I have never heard of the Luftwaffe using it. I am especially surprised if it was found in a synchronised installation.. The synchronisation system used for electric priming was different from that needed for percussion priming. I presume that the example found was a test or experimental installation.

 

[thehairbarebunch]

Hi Blackwatch,

I'd like to see the pictures of the percussion primed MG131 you found on the FW190. For the reasons Tony has outlined it is very surprising to hear that it was a, mounted on an FW190 in the first place and b, used in a synchronized installation.

As I understand it very early production, c.1939, was percussion primed thereafter almost all had electric "Zundhutchen J" primers.

Regards

 

[Falcon]

I bet during the last days of the war there were aircraft that were left on the ground where no Mg151 ammunition with the correct primers could be found as allied bombers flew overhead.

 

[blackwatch]

A picture of the percussion primed 13 mm(mg131) case.

 

[thehairbarebunch]

Thanks for the pics.

It is one of the early 1939 P coded cases. Quite what it was doing in the wreckage of a FW190 is beyond me !