"Men against Tanks, A History of Ant-Tank Warfare" by John Weeks.
Ammunition type, range and penetration. Armour type not specified.
Various 20mm, range 400yds, penetr. 0,6-1 inch
Boys AT-Rifle, range 300yds, penetr. 0,5inch
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"Handbook on USSR Military forces".
12,7mm MG with B-22 API, 200yds, pen. 20mm
20mm ShVAK BS API, 1000yds, pen. 25mm
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"Technical Ammunition Guide series2 pamphlet8, British AT-rifle ammunition 1917-1945" by Labbet&Brown. 7 out from 10 bullets penetrated armour, range 100m, angle of hit 20 degree.
Boys AT-rifle, cartridge SA AP .55inch Mk1, penetr. 16mm and with Mk2 ammunition 19mm.
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"Military Small arms of the 20th century", Hogg&Weeks.
Boys AT-Rifle, 300yds, angle 0 degree, pen.21mm
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"WW2 Tanks", Eric Grove.
20mm KWK30, range 500m, Angle 0 degr., penetr.24mm
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I couldn't find penetration data for .50cal (12,7mm) but if 20mm AT-rifles and cannons had problems to penetrate 20mm armour even from optimal angle from 100meter I found it hard to believe 12,7mm can kill/disable tanks.
Does anyone have penetr.values for Hispano?