I shot a deer with one a few years back. Horrible penetration compared to my Zwickey and VPA glue on heads but, fun to make and look cool.
I've made em for 20+ years and killed a dozen hogs and deer with several kinds of stone points. My penetration on hogs with a longbow and recurve rivals anything any steel head has done...recurve or compound. I feel that a well made stone point will out penetrate most steel heads. Obsidian is not one of my favorite materials but it will kill even when I breaks on bone, the broken edge is scalple sharp. The only material I would not use on a deer/hog again is Tallahatta Quartzite because it is weak when thinned enough to make a good arrowhead and will break on contacting bone. It is a native Alabama stone material and there have been thousands of real native atlatl points made of it, but those points usuallly run larger and thicker than the size needed for an arrowhead.
