Hi I'm trying to get my head around maths. Sabot .. "This, in combination with the sub-projectiles’ higher sectional density, gives the resulting sub-projectile vastly reduced aerodynamic drag in comparison to the APCR. Both the higher initial velocity and the reduced drag result in high velocity at impact." For concrete "The penetration depth increases almost linearly with impact velocity in that range . " Ian V Hogg - 2013 - "This was the Röchling anti-concrete shell (Rö-Geschoss), ... passing through 3m of earth cover, 36m of concrete, a layer of broken stone, gun casement and 5m into the earth .." ---------- Resistance drag in air in given conditions is Area. Velocity sq. A modern sabot is about 5 /18 core / calibre, A is 4%. As KE is .5 M Vsq then the area being the size of mass the velocity sq is the inverse at 2500% . So the 5 times increased velocity matches the reduced area giving same drag. Artillery shells penetrate around .6 m into concrete with resistance as ~ Mass . Velocity. Penetration rises by about .6 with triple the velocity so raising velocity by 5 should double to 1.2m. How then did the Germans get 36m concrete + 8m earth?