cottonstalk, i like, and this is just on my experience, over 1500 fps for the aframe and over 1700 from the barnes and this is muzzle velocity. i recently killed a whitetail doe with a hornady xtp 240 mag at 2050 fps and hit it quartering to me from the right front of shoulder and out the back ribs. crumpled at the shot no spine hit. so far i've not had any deer exotic or whitetail not drop in their tracks with expandables running mv over 1750 fps. i've shot over 10 oryx now and i've dropped them all within 60 yards, now i do shoot african animals till they quit moving with any bullet, but i've not had the same results with the hardcast. last oryx shot with a 475 through the lungs went over 6 miles. cape buffalo with an aframe and did massive damage and left me a wonderful blood trail from the nose, it was easy to follow, due in large part to the damage the bullet did. per the ph woulda died on the first shot but we don't let em suffer so we pushed and shot it again with a buster which is my f/u bullet, on testing on the actual animal, a 475 hardcast produced no more penetration when shot through the same shoulders next to the original hole. the 45 colt shot animals and 44 mag shot animals with expandables did not penetrate nor do the damage on 400lb and up animals that the faster bullets do if under 1400 fps where ya choose to load a 45 colt 5 shot is up to you but i'm keeping with book velocities. 475 expandables of premium bullets do great above 1400 fps. another great example is the 4 black bear over 300lbs we took in alaska. 454's and a 475, all premium epxandables the 475 i believe was about 1450fps on a 325 gr speer (gary's) and the others were 2 with 300 gr partitions at 1600fps and a barnes 250gr xbp at 1750. all dropped within 20 yards. my sons bear was a 250 gr barnes at 1750 fps at 50 yards through both shoulders, didn't take a step but rolled 20 yards down the mountain. never got up and took a step. no tracking involved. 5/5. on my 11 bison i've shot i've used hardcast 44 mag, 45 colt, 454, and 475 and expandables in the 454 and 44 mag. the ones through the heart killed quickly, but one with a 454 hardcast and a 45 colt hardcast dropped at the spot because of the bone trauma but took over 5 minutes to die as they were not shot throught he heart and the other animals herded around them precluding a f/u shot. none of the expandables went further than 40 yards and that includes the 44 mag shot with 225 hornday tipped hollow points through the lungs. a water buffalo shot with the barnes xbp died with one shot and traveled about 40 yards before it layed up and died. two cow elk shot with hardcast, one with a 45/70 and one with a 475 had bullet failure on the shoulders and required a 200 yard chase and follow ups which brought them down quickly. that said the other elk i've beenin on the shooting with 454 hornady 240 gr xtp mag bullets and a 275 gr barnes xbp bullets piled up within 20 yards. gary shot a huge cow elk bigger than many bulls with his 475 with speer 325 gr bullets and he waylaid that thing and it dropped within 40 yards if i remember correctly. my sons lion which is on video was shot with a 275 gr xbp bullet head on and it traversed the entire lion and went through 2 small trees, the f/u shot from the back b/w the shoulder blades was the final killer and as the video shows as the lion jumped up to charge but fell at the first step in a heap illustrates where a smaller wound channel and taking a couple minutes to die is not desireable. quite exciting btw. gary's lion with the nosler partition out of his 454 went about 5 feet and died. sure poor shots out of the vitals inspire a lengthy tracking episode. experience varies and this is just some of mine and what i base my opinions on.