maximum range vs weapon accuracy; warhead vs penetration

[jp10]

Originally Posted by raginis

"... It doesn't tell you how much warhead size affects penetration,

If you mean in real life, early WW2 HEAT rounds had a penetration 1.5 to 2.5 times their diameter. Modern HEAT is published as much as 7X Diameter.
This assumes the detonation is at 90 degrees to the armor face (0 degrees deflection) and at the proper standoff distance for the explosive jet to form. Most jets dissipate by 6 feet (2 meters).

There is no fixed diameter times X calculation since the increase in penetration depends upon internal material, explosive type, cone materials and cone angle designs. Tandem explosive HEAT warheads have been created to defeat reactive armor.

HEAT charges lose penetration if spinning so most accuracy is effected by being fin stabilized. RPG and LAW rounds were prone to wind effects.