WW II Ballistics: Armor and Gunnery Fail

The strangest thing happened on the way to the forum.  WWII Ballistics Armor and Gunnery book by Lorrin Bird and Robert Livingston was changed after printing two editions.  I have copies of the first and second edition but it is different than the copy at the Copyright Office.  This is a legitimate version and not like I thought a first a hoax.  So it was made after the edition I received.  What has happened is some Soviet cannon data has been changed.   Link
Look at the 100mm AP-HE  and 122mm AP-HE.   They are considerably different.  . 
Maybe in the Copyright issue he used the flawed Soviet ballistics to calculate his values without checking them. 


Miles Krogfus has pointed out that the 1931-38 era firing tables for the 122mm Corps cannon 1931(A-19) was incorrect.   Below on the left is a 1944 firing table that shows the errors.  This was not revised correctly until the late 1950s.   On the right is a corrected Firing Table of the 1960-70s     The 100mm BS-3 BR-412 round strike velocities are also incorrect. This captured and translated firing table of the similar 100mm D-10 is correct  Korean War version.  The strike velocities are within +/- 2 m/s of the Sept. 1962 DDR firing table of the D-10 gun.   The difference was the MV of the BS-3 was 900m/s while the MV of the D-10 was 895 m/s. (Jane's puts the MV of both guns with BR-412 as 895m/s) (The Russian Wiki puts the MV of both guns as 897 m/s.)

If one wants generated data the Naval Armor and Ballistic program can produce a table.  Compare this to the generated US data at Wikipedia.

The US produced a graph of the armor protection criteria of the 100mm BR-412B.   It is based on an incorrect estimated muzzle velocity.  When plotted to the correct MV a different picture arises, Here are shown the actual striking velocities at various ranges where the penetration protection values can be seen.

Click to enlarge

Generated Penetration tables from true ballistic data.
Shell 35 lb.
Windscreen of BR-412B: 0.7 lb.
Shell quality of 0.77.
Armor is WWII Class "B" homogeneous steel.
Penetration Criteria is US Naval Ballistic Limit.
Penetration calculations based on HCWCLCR program formula by Nathan Okun.   

Note- Shell quality is speculative and is not part of HCWCLCR.

On this graph protection criteria is 157mm at 1000 meters a little more than the 155mm the NAAB generated NBL penetration.   The Wiki says their firing table number of 211mm is the US penetration criteria at 500 meters.   The US protection level from the graph is 167 mm.  It seems unreasonable the US would have the protection level less than their penetration level.   

The NAAB penetration at 500m is 164 mm.   
Note - The document states the MV is estimated.   The protection values are not.
CIA captured Soviet 100mm BR-412D Firing Table

Soviet 100mm Report Multiple Firing Tables  1957

122mm BR-471B shell US protection criteria to the left.   

Click to enlarge.