The strangest thing happened on the way to the forum. WWII Ballistics Armor and Gunnery 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 thought a first a hoax. So it made after the edition I received. What has happened is some Soviet cannon data have 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. In 1944 this was revised but was still wrong. It was not revised correctly until the 1960s. The example of this error can be found in the captured and translated 1951 firing table for the 122mm the time of fight of a BR-471 shell to 3000m takes only 4.2 seconds. In a corrected Firing Table of the 1960s the time of flight to strike range at 3000m is 5.0 seconds. A similar thing may have happened for the 100mm D-10T BR-412 round. I don't have a 1960s WWII firing table if there is one so I can't compare it to the WW II version. (The Russian sites seem to take
the data as correct.) 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.