30mm DEFA experimentals


#1

I know very little about these. I inserted them and if they fit, I am showing that in these photos. The very dark green cartridge has no headstamp, is longer that the other cartridge and appears to have slight necking about an inch from the mouth. It is labeled “Thin wall steel ctg case”.






#2

sksvlad,

The brass case (30x112mmB) is the French DEFA 550 series. The steel case is very interesting (as is the projectile in it), longer and shouldered (?), hopefully someone can ID it. Does it have a headstamp?

One projectile appears to have a base tracer element.

Interesting items!

Brian


#3

Brian, the “brass” case is a zinc plated steel case. The black one sould be South African. It would help to see the hs.

The projectiles do not belong to this caliber to what I see (as per the driving bands). If seated on the case the round should not be longer than a regular 30x113B then. One needs to compare.
The odd shaped projectile (experimental to what we know) is made for use with a discarding sabot (cup type) and could be for a 35x228 (this is where I have seen them being used). Thsi here also can be a 30mm derivate, too little is known.


#4

Here are both the headstamps. The projectile with a stalk at the bottom has threading inside of that stalk, and the whole bottom with the stalk looks like it was screwed in itself into projectile’s body. Sorry for poor photo quality, we have snow/ice storms which prevent me from doing photos outdoors.



#5

The Cad plated steel cart. was manufactured in Australia by MF Munitions Footscray in 1975, the stencilling on the side indicates it was filled @ Saint Marys filling factory (MY) in 1976.

A relatively common cart here in Australia, but the projectiles are very obscure!

Regards Ozzi.


#6

Vlad, I noticed only now that he black case is longer than the Australian one which should be 113mm.
What is the case length of the black one then? I guess South Africa is no option anymore.


#7

The black one is 118mm long but otherwise looks identical to the Australian one (besides the necking).


#8

[quote=“EOD”]Vlad, I noticed only now that he black case is longer than the Australian one which should be 113mm.

EOD,

That’s what I was questioning/alluding to in my post earlier:-).

Not long enough to be the GIAT 30 (now Nexter 30) which is 30x150mmB. And it appears to have a very slight shoulder.

Neat items Vlad and good feedback from forum members!

Brian


#9

Here is a better view of the shoulder in the dark round


#10

I have asked the author of the book « The story of the 30 mm DEFA aircraft revolver guns ans their ammunition » (IAA N°494 pg 48) what he thinks about this case.

He said me that at the first glance it could be a trial from South Africa to increase the velocity of the shell for DEFA guns. But there is a problem as it seems, on the picture, that the base of the case doesn’t bear the circular depression around the primer. So it can’t be used neither with a standard DEFA gun nor with an ADEN gun (closure of the electrical circuit for the last gun). Moreover, the primer pocket seems to have drilled.

If the case had been developed for a modified DEFA gun or a gun using a cylinder with same measurements, the 5 mm longer case increases the velocity of the shell as it allows a larger volume of the propellant and but decreases the terminal efficacity of the shorter shell which contains less high explosive. Also the pressure is higher. As the shell is lighter, the velocity decreases quicker with another problem for air to ground application : for a API shell the lower impact velocity gives a less efficent impact.

There is also another theorical possibility he said : perhaps RSA had tried or wanted to develop a gun with a longer receiver which may use a longer round but the project quickly may have vanished.

chassepot


#11



The primer well bears circular marks such as in drilling.