I agree with Oldtimr. I hunt with Barnes TTSX bullets in my .300 Weatherby only because they are accurate in that rifle, and my Leupold CDS scope is calibrated for those bullets. I've also hunted with Barnes TSX bullets in my .375 RUM, but again because those bullets are very accurate in that rifle. I've been hunting both mule and whitetail deer for over 50 years, and have killed dozens of them without any trouble with both lead and copper jacketed lead bullets. I killed my largest antlered mule deer, a couple of black bears, and an American Buffalo with plain or cast lead bullets. Its more about bullet placement than bullet composition.