They believed that body shots were needed to kill an elephant reliably. Thus, the huge bore bullets used to gain the needed penetration.

Tradition, and a reluctance to embrace a "new concept" . . . . a well placed small caliber higher velocity bullet, caused the "delay" in change. In hindsight one might consider how much harder it would be to place that bullet in an elephant's heart than to place one in its brain (and the fact that a heart shot while fatal is not instantaneous, as is a brain shot).

May God bless America and those who defend her.