Mostly because you won’t be using everything on an auto-progressive turret and the setup is not easy. For a beginner, it will take you quite a while because, in an auto-progressive, a lot of things happen at once: decapping, resizing, powder trickling, bullet seating die, etc. No press is made 100% reloading press for accuracy and durability first time, which means you must have the eye of an experienced loader to be able to see the flaws.