We changed the design of our Safety Prime in June 2017. The new design provides better contact between the Safety Prime trigger and the primer cup. We recommend using the new design with the Auto Breech Lock Pro. The previous Safety Prime versions may not work as reliably as the new design. If you are interested in upgrading to the latest Safety Prime tool, you may take advantage of our lifetime guarantee. Please return your old style Safety Prime to us with a note that you wish to upgrade, and we can exchange it for you for 1/2 the current retail price, $15.00 + $8.00 shipping = $23.00