I've cracked the nock end of a bunch of carbons when I hit something hard and the nock wedged the shaft so bad it split. I've also whacked a rock and had the insert and all the shaft's guts come spiralling out of the shaft when I picked it up. That's happened a couple of times with Gold Tips. I've also snapped quite a few in two when hitting a metal target stand. They always break about a half inch in front of the fletches.