I focus on energy. because energy is what causes damage, "low terminal velocity" or not. Read up a bit on Civil War snipers and see what kinds of holdovers and windages they had to contend with. The target is both big and fragile. A hit almost anywhere with 270 ft-pounds concentrated in that small area is very likely to cause non-survivable damage.
Read about them? I linked to them in my post #26.