Hornady's Lock-N-Load bullet feeder dies are a new and innovative way to feed bullets in your progressive press. Designed to work with the Hornady Lock-N-Load Bullet feeder system, these dies use a unique two-colleted system that allows only one bullet to drop onto the expanded case mouth at a time. Can be used without the Lock-N-Load bullet feeder assembly in a more limited capacity to free up your hands. The Lock-N-Load Bullet Feeder is designed to work with any progressive press with standard 7/8"-14 die threads and has been found to increase reloading speed up to 50%. These feeder dies are case activated, meaning a bullet will only be fed upon contact with the case. The collets are constructed of solid steel and are durable enough for years of reloading.