German 50mm AP

I wanted to make an accurate ballistic model of the German 50mm guns.   Particularly that of  two armor piercing shells.   The first is an early uncapped APHE ogive shaped shell noted as Pzgr.Gr. The second is a later capped APHE shell noted as Pzgr. 39. Both weigh the same 2.06 kg.
To model the ballistics I need the velocity of at least two different points.   The more the batter.

Now, I have found that Lorrin Bird ("Rexford") had posted in 2002 or so a Firing table of the 50mm/L60 (fig 2.)  This seems to be correct as the numbers are almost identical to the data found in  "Handbuch der Flugzeug Bordwaffenmunition 1936 - 1945" (fig

Fig 1.

3.).  It would be nice is the Rexford data was for the early uncapped shell as the other is clearly for Pzgr. 39.  But, that is speculation.

Looking next to penetration for these shells several data sets can be found.  This especially, true of the Pzgr 39 shell.  The Germans obviously had test data, and so does the US.  The Russian have some sketchy tests.   The Yugoslavs have post war tests which are consistent with other tests..  I would of thought the British War Office would of done testing as well.  And these would of turned up in British authors WWII theme books, as there are a lot of them.  It turns out, not so much.   Comparing the data in these it looks like it matches pretty closely to German data. (Fig 4.)   In fact this seems to match (+/- 1.5 mm) the BIOS data of post war intelligence on German weapons.  The BIOS data probably is from earlier German weapons material such as the previously mentioned. DIE VORGÄNGE BEIM BESCHUß VON PANZERPLATTEN, Lilienthalgesellschaft für Luftfahrtforschung 166 (Berlin 1943) (Fig. 5  blue line)   What matters to this game is that I normalize* data depending on it's source.  (If British WO data then a difference multiple has to be applied to the numbers than German test data, i.e different normalization.) 
The one thing that doesn't match any data I found was the penetration data for the early Pzgr Gr shell. (line in red)  The penetration curve for that is completely unreal.  The penetration of the Pzgr 39 shell (blue line ) exactly matches that in the German table data as well as the BIOS data.  So the table data on the early shell looks like it to be a weak version of the Pzgr 39 shell, but this graph shows it com

Fig 2.

Fig 3.

Fig 4. Source Panzer world   and here

Fig 5.

pletely different.   I'm not going to say this is an error but it would be the only shell where the early version is more powerful at some ranges than the improved Pzgr. 39 shell that replaced it.

Right now Panzer War uses the table data for the early shells rather than the graphical data.

Awaiting more info.

*Normalization refers to the creation of shifted and scaled versions of statistics, where the intention is that these normalized values allow the comparison of corresponding normalized values for different data sets in a way that eliminates the effects of certain gross influences.