o.k. charlie u asked for it!
i know that your statement on the cow that stood there for 15-20 mins. is correct, last fall i to shot a elk with bow and the arrow went blazing on down the ridge! she just ran about 30 yards and stood there! 23 mins. later a whitetail spooked her and she walked down the hill. we found her within 100 yards of where i shot. i opened her up and sure enough the arrow passed threw both lungs.
after this i studied bow hunting alot! i didn't want to have an animal last that long after a bow shot. what i have found is inlike a gun, with an arrow u want to hit the heart! PERIOD! an arrow kills by what? loss of blood, the heart is what pumps the blood= no heart no pumping. so this year i will hit the heart or under shoot all my game.