WW2 German 20mm case ID

[ammofo]

I'm having a bit of a sort through my cases for a forthcoming military fair at Marks Tey near Colchester, and want to answer a question that I've had for a while regarding my WW2 German 20mm stuff.
I know earlier (and pre) WW2 ones were brass, then they turned to steel, but I've also got a few later examples in "field colours" (one green, one brown). I presume these were just for cammo purposes, but the brown one has a yellow stripe round the mouth of the case. Does anyone know what this signifies ?

It would be nice to see some shots of other collectors' examples too, as these are one of my favourite cases and I'll probably keep them and add to them in the future. Sorry about the weird angle that makes them all look different sizes !!

 

[smle2009]

not too sure about the 20x138B but a coloured neck seal on smaller stuff(7.92,9mm ect and some of the other 20mm's) signified tropical use(tropen) and the colour usually corresponds with the load,in this case,yellow = HE.
Must admit though I have never come across this on the 20x138B before,so could be very wrong about this.

Atb
Tony

 

[ammofo]

Did the tropical stuff have a coating of some kind to prevent moisture, as this brown case does have a lacquer of sorts which, bizarrely, likes to go a bit mouldy every now and again. I've always found it to be a bit ugly to say the least, but I've hung on to it as I've not seen another like it yet...

 

[blackwatch]

My collection of2 cm flak rounds



The 2 cm flak rounds for tropical use are painted black or red (case mounth and primer)
Green and brown laquered cases are standard on the steel cases.

 

[ammofo]

Any idea what the yellow ring denotes around the rim ?