tho; they were made for a lot of calbers, up to 300WM. The design of the system is basicaly as Bench Rest shooters use. It trues up the inside and outside of the case necks, and trims them to length. Once the cases are fire formed to your rifle; than you use this system for your "chamber only". There is no full length resizing; nor do you have to with this system. Longer case life, and a way more accuracy. I personally use this system for my 25-06.