Dr. Ed Ashby has been doing research on arrow penetration for about 2 decades now and his research will clearly answer many of the questions and theories being expressed here. You can find a presentation that he made to the Michigan Bowhunters at the Tuffhead broadhead site. Dr. Ashby talks about momentum vs kinetic energy, showing that momentum is highly correlated to increased penetration, so the advice about heavy arrows is very good. Dr. Ashby shows a correlation between penetration and arrows that are above 650 grains. It would be very good to go through his entire presentation, including his presentation on the New Guinea people shooting the 4000 grain arrows, which by the way are not fletched, which further increases their quietness.
PAHunter, get David Petersen's book A Man Made of Elk, , He will clearly explain what it takes to get an elk with a self bow. He is what I would consider an authority on elk hunting in Colorado. For those deer hunters who have not taken elk with a bow, it is much different. Elk are harder to bring down. Shot placement, heavy arrows, and sharp broadheads are very important, as always! I got a cow elk last year and I went through much of the same mental exercise as PAHunter.
