451_Detonics
Grandmaster
For me one big advantage of the 550 is the sheer number of caliber I load. My machines currently have heads set up in 15 different calibers. When I was shooting action pistol several times a month and burning through 3-4000 rounds a week in practice my 650 set up in 38 Super made sense but I don't shoot at near that volume anymore. I currently have 2 550 set up, one in small primer and on in large. I can do a simple die head and base plate change and go from loading handgun to rifle in just minutes.