WW II Ballistics -Russian 152mm Guns

The ballistics data of the Russian 152mm guns seem to have a problem.  As with other 1939 and earlier Russian firing tables they are in error.  The early firing table can be found on page 25 here.  PDF link  It has no striking velocities on any shell table.  But time of fights are listed.   These unfortunately don't make any sense.  The BR-540 APHE shell takes just as long to travel the first 500 meters as does it take to travel from 1500m to 2000m.  Thus it doesn't lose any velocity.    On the other hand the 152mm ML-10 firing tables have been updated, corrected and released in 1968.  This does have actual firing tables for the shorter 152mm gun.  Link DJVU     The 152mm ML-20 report does have a penetration table (left).   This is a calculated result using the DeMarre formula with K=2400.  Since it is cal

culated one should be able to backwards derive the impact velocity.   Unfortunately doing this only produces unrealistic ballistics.    So my solution is to use the ballistic coefficient found by the ML-10 tables for the ML-20 gun.   

DeMarre Calculation program download.

The BR-540 shell (right) was used by both ML-10 and ML-20 guns. 

The ML-10 firing table updated and released in 1968 (left) has striking velocities as well as correct time-of-flights.   The MV is only 40 m/s less than the ML-20 so solving for the ballistics would work for both guns.   In the above image the striking impact values from the firing table are plotted (red boxes) where a ballistic solution can be found.   When the actual ballistic coefficient of the ML-10 is used with a MV of 600 m/s it produces the blue line.   This shell was introduced after May 1943. Citation.

Note - small blue triangles show where solving for velocity using DeMarre with the ML-20 leads one.
The blue triangles also represent the ballistics of the O-530 HE shell.  It looks like the Russians just recycled the ballistics of the O-530 HE shell for the BR-540 without testing.
Another shell used late war by the ML-20 was the BR-540B, an APBC blunt nosed projectile.  I haven't found any reliable data on this shell's ballistics.   It may be close to that of the US M-112 APCBC shell fired from the 155mm gun/howitzer.  The M-1 Long Tom is probably too high a velocity but the M-1917 155mm is more in the same league.  The M-112 shell has a ballistic cap like the BR-540B shell.   
The graph below right show the comparison of the M-112 shell with that of and estimated ballistics of the BR-540B shell.     

The BR-540B shell (left) was used by ML-20 and later guns.

The penetration of the US 155mm M-1 Long Tom and other US 155mm guns are found in original sources: US gun data 1   US gun data 2.
The data for the 155mm M-1 is entered into NAAB and the shell quality is varied until the penetration output matches that in the data table.  (I couldn't come up with a single shell quality factor that works for all three guns, it is an average.) Then the data and ballistics for the Russian shells are plugged into NAAB to find the penetration figures.  The same average shell quality of the 155mm gun shell is used to model the Russian shells.   The resulting penetration data is used in the tables on page 58 and in Panzer War.   

It's a little more complicated.  The table penetration data is Aberdeen data so would be in 240 BHN armor.  Which is what Class B homogeneous armor is.  So the penetration values produced by NAAB have to be run through adjustments to get 270 BHN armor as used in our tables.

Shell weights found  page 341- 347 CIA document here:  link PDF