When I was a teen I found an ax head, the strap marks were still easily seen. A friend, a former friend, stole it and refused to give it back. Anyway, on a Canadian canoe trip we crossed paths with a trad hunter that used, I think, a sinew backed mulberry bow for moose. He had pictures on his Iphone. He was using obsidian heads. The first shot at a moose, his arrow failed somehow and he got no penetration. His second shot went straight through it. From the photos of the short blood trail, proved that the head was massively effective. He shaped his heads after one that he found, about 2.5 inches long and one inch wide and slightly spoon shaped. Later they challenged us for a canoe race to an island that was about two miles away. My wife and myself, we beat them by over 200 yards.