The RCBS Rock Chucker Supreme Auto Priming Unit is a game-changer for reloaders, transforming the traditional one-at-a-time priming process into a more efficient tube-fed system, eliminating the need to handle individual primers. Easy-to install, it attaches in the same location as the standard priming arm. To use, simply attach the correct primer cup and seat plug to the priming arm slide, insert the appropriate primer tube and safety shield and fill the tube with primers. Once set up, the reloader is ready-to prime. The straight push-pull primer arm slide is designed to minimize the chances of primers falling out of the primer seat plug, ensuring smoother and more reliable operation. This upgrade enhances both speed and safety, making the priming process quicker and more consistent.