Have done a lot of reading and research. In talking with local archery shop and owners of Alaskan Bowhunting Supply and many who have done this hunt before I am prepared to go finish my Dangerous game archery quest. To this point, I have taken a lion, leopard free range with lighter set ups but the Cape Buffalo I hunted required a Mathews Reezen with custom 80 pound limbs. Drove a 900 grain arrow tipped with a solid forged 200 grain broadhead thru both lungs at 12 yards.This set up NOT enough for hippo or elephant. I am using a 80 # Mathews Monster XLR8. Bow rated IBO of 363 FPS. I am using a custom arrow built by Alaskan Bowhunting Supply that weighs 1260 gr with a 40 % FOC when topped with a steel forged Nanook Right bevel broad head, blazer veins.I am currently chrono'd at 190 FPS, 100 FPKE and 1.04 momentum and am pulling only 73 pounds This bow is fast. I leave in a month and will be at 80 pounds driving my KE over 110 FPKE and momentum #'s that will give me all the confidence i need to make a great ethical shot. I see a lot of talk about bow poundage but thats not the only important factor with todays modern, faster set ups. Get that arrow weight/spine up, get that FOC over 25% , use a forged steel one piece broadhead that weighs over 300 gr and get your KE over 100 FP and momentum over 1.05 and you will drive that arrow into the sweet spot rib bone or no rib bone. Hope this helps those who are interested. Not a lot of actual data out there but Dr Ashbys writings on arrow KE and Momentum are a great start.