I own a Barnett Razr, and recently just bought a Scorpyd Ventilator Extreme. Both of those manufactures do not call for flat nocks to be used with the two bows I have. Barnett Razr calls for moon nocks only, and Scorpyd calls for capture nocks only, never use flat nocks. My Razr broke the string twice on me within a week, and I strongly believed that even with the moon nock, the string may have jumped or jacked the string. Because prior to pulling the trigger, I physically checked to make sure the arrow was seated all the way back against the string, off color vane faced down, and the nock faced the string properly. So, the string may have really jumped or jacked up the arrow. My personal opinion is capture nocks will suit the best for safety wise!!!! And it will be safer to shoot your arrow with capture nock than flat nock.