I tried them out in .223 and it killed my son's first whitetail. However, there was a very small entry and zero exit but the inside's were wrecked. The deer went maybe 40 yards and fell over dead. I moved away from them because I didn't like the zero blood trail and no exit. Perhaps the .300 would work different but I'm not willing to wound an animal on a bullet that "blows up" inside the animal.