The Iroquois had invented 'rifled' arrowhead long before they found themselves face to face with or in possession of rifled fire arms. (62) It does not seem likely that the spiralling is sufficient to rotate the arrow rapidly enough that the need for feathers is eliminated. This at least has not proved to be the case with my own sample. Evidently such was not the objective. What is clearly achieved is a far more serious wound. Like the outlawed dum-dum bullets of World War I, the form of the head is such that the arrow does not pass right through (where it could easily be withdrawn) but buries itself in the flesh and stops there. The energy of the arrow is absorbed as the head 'corkscrews' into the body.
— Achievements of Ancient High Civilizations
The whole thing is amazing.