I love my SDB. Only thing with changing calibers I don't like is actually changing from small to large primers or vice-versa. I load 9mm, .357 and am trying to find cheap 45 auto dies and shell plate for mine and when I do, I will only load small primer 45 so I don't have to change the primer mechanism.
I've read this about the Square Deal issue with primer size before. And apparently swapping on the 550 isn't much better.
It does suggest that a person could do worse than to buy TWO Square Deal presses with one in each primer size and then buy the dies and shell plates as needed. Here again the only downside is that you're limited to Dillon dies to fit the Square Deal die plate.


















































