unusual Dienstglas 6x30 reticle

[Stew]

I attach a pic of a cxn 6x30 which contains an unusual reticle.
It seems to be the standard Dienstglas 6x30 horizontal grid pattern (40mils- 0-40mils)with an unusual roundel above.The diameter of the roundel appears to be 20 mils
Any ideas as to the purpose of this specialised reticle ?
The reticle picture shows a ferry approx range 1.2 kms
Thanks.

[Stew]

Dienstglas 6x30 cxn

I attach a pic of the 6x30 's

[Sgt Bilko]

Another Stew - maybe for air defence?

http://www.ebay.co.uk/itm/WWII-GERMA...gAAOSwbdpWVHJ6

[Stew]

thank you Sgt Bilco. Always good to see a second example from the same serial # range.
Interesting that subsequent production cxn Dienstglas 6x30 returned to the standard reticle pattern.

[MAUSER99]

Stew, Im thinking its something cxn did. I have a set of cxn 7x50 with that same range grid and bulls eye. I just thought it was some thing special with them. Never seen that grid in a set of 6x30's by any maker.
Hope this helps. I will dig them out and post the data.