Users have reported that the primers in the tray of an Auto Prime can explode for various reasons, some of which include: a cocked primer, or an attempt to prime a case which has a primer already in place, or more than one primer on the punch, or priming a military case with the crimp not completely removed. Should an explosion occur, our tests have demonstrated that safety glasses will normally prevent serious injury to the user if CCI or Winchester primers are used, because the explosion is minimal. Other primers, however, can explode with sufficient force to seriously injure the user, or persons nearby. We do not take any position with respect to the quality or performance of primers available on the market. However, only those primers manufactured by CCI or Winchester are recommended for use in the Lee Auto Prime, and when loading those primers, safety glasses should always be used. No other primers should be used with the Lee Auto Prime.