I started out with a 550 and have loaded 9mm, 40 and .223 on it. A friend gave me a Turret Press and I loaded some .308 on it. I moved on to a 650 and load everything but .308 on it. I would suggest the 650. The auto indexing and case feeder can greatly increases your speed and lessens fatigue. You are just one step away from "only" having to crank the handle by adding a bullet feeder. Before Mark 7 came around it was uncommon to hear of somebody moving away from Dillon.... and pretty rare somebody went down in the series... From a 650 to a 550, etc.