Just found on egun..and not my field 95x355mm reformed, what is it

Here found on egun.de
As it is too big for me :-), I do not know anything about it.
But as it is made under use of a germen DM4 case and bearing a british broad arrow? I am interested in to learn more…
It has beside the primer a separate hole in the base (for what?) and it was made from a 105x617 case (dims in mm)…
I Show the pics from that auction (so they are not mine)
Side-and inner view:

I think you mean 105x617, not 106x617.
The second hole in the base seems to whisper “pressure measurement” in my view.

Pressure measurement is correct. These cases had shown up in the early 1990s amongst scrap metal of Rheinmetall.
I never saw these identified. Sure another nameless test of something.

thick finger…:-)
measurement corrected,to 105, thx