I am building a heavy arrow for my hunt this coming year in SA and I wanted to put it out on AH for comments. I want to be ready in case I decide to add a cow Buffalo or Giraffe to my plains game list. I bought a dozen Easton FMJ dangerous game arrows. They are 300 spine and 15.5 gpi. My draw is 29 inches and my current bow is a Mathews MR5 set around 70 lbs. Arrow weight with hit insert, knock and vanes is 472 grains. Add in a VPA 300 grain 2 blade and a weight tube in the arrow at 5gpi and my total will be around 910 grains. I have read numerous articles saying to get to 850 or higher. What do you think? I got a zebra, warthog, Nyala and Impala in 2014 with an arrow/broadhead set up in the 450 grain range and had pass throughs on all with my 2007, 70 lb Black Diamond bow that is considerable slower than my MR5. Thx!