I've been researching to determine the damage potential between normal gun AP rounds and APHE rounds with a small HE cavity in the rear of the shell.
What I'm finding is that the APHE round, while having real potential for additional damage by delaying the detonation of the HE after penetration, combat results, and range testing, did not prove this to be the end result.
Making a cavity in the base of the AP round for the HE meant less mass in the round, which resulted in 5-10% less penetration.
A round would need to penetrate about 20% more than the armor thickness for the entire round to penetrate intact into the fighting compartment and for the delayed HE charge in the rear to detonate. Since the HE charge is in the rear of the shell, a partial penetration or the shell breaking up during penetration would have almost no effect.
If you are assured of total penetration, an APHE round is ideal. However, if you need more penetration, a solid AP round is better with 5-10% more penetration.
Diminishing returns of HE filler: By the later stages of World War II, many ordnance designs either used smaller HE fillers or abandoned them altogether. It was determined that a few kilograms of high-velocity metal was so destructive that the effect of a small explosive charge was negligible. A successful penetration by a kinetic energy round alone was often enough to knock a tank out of action. Penetration was more important.
IIRC, the US used solid AP rounds for their guns towards the end of the war. I think the Germans stayed with the APHE because they had no problem penetrating most Allied armor.
My conclusion is that the effect of APHE is negligible, and I will not include it in my damage model. Does anyone have more info or disagree with this conclusion?
Wolfhag
