Has anyone ever did any real life testing in the modern day with this type of arrow heads? I just wonder how well they penetrate, if they were used more than once, etcc.
The vast majority of “arrowheads” are used up knives. When chert was used to tip an arrow, most were simple small triangles with notches, although in some regions some of them did have some narrow notches. When we look at historical arrows, many are actually tipped with bone points. In fact knapped stone on arrows is not super common UNLESS the arrows were used for warfare. Spears and atlatl darts same - VERY few flint points on them, flint is just so delicate that of the available materials you are better off using bone/antler, and bone points kill just fine.
As for testing them, yes, definitely. I have taken over 30 deer with stone points and a selfbow I made. They penetrate great when made and attached properly. What you do not want to make the mistake of doing is using something shaped like one of the used up knives commonly found in fields. Those were not made to penetrate, and after a few resharpenings they penetrate even less. I had complete pass throughs on maybe 1/3 of my deer - but keep in mind I was using 34 inch long 800-plus grain arrows and keeping shots under 20 yards, most shots in the 10-15 yard zone, with a 55 pound osage selfbow. The very first deer I killed with a flint point hit between the ribs going in, broke a rib coming out (also broke the flint point) and just the fletchings were still in the deer as it ran off and the arrow was laying on the ground about 20 yards from where the deer was hit. I was surprised, I wasn’t expecting that much penetration. But many more deer proved it was not a fluke.