Cossack makes a good point about proper "capture" or "moon" nock alignment. While doing so is a simple process, not doing so can lead to significant damage.

Good freind of mine bought the same cross bow that I was shooting ..... a Parker Tornado. Moon or capture nocks are specified. One afternooon, he had a group of fat does ease in almost as soon as he had gotten set up in his stand. He not loaded a bolt yet. Slid one in. Thought it was aligned. Not the case. Fired .... bolt flipped off to the side and fell to the ground. The dry-fire resulted in both limbs splitting nearly full length. To his surprise, Parker replaced the limbs at no cost.