I would say its between the 550 and the LNL. The 650 while nice would cost a mint to get set up. How easy is it to remove the case feeder for the 550 to load rifle? Or is it even worth it to get it for the 550?
The 550 really doesn't do badly without a case feeder or auto advance. Compared to the 650 it really isn't a huge difference in production rates which surprised me. The 550 is an example of a good design. Once you start producing ammo you understand what I mean.
What I didn't realize when I bought the 650 6 years ago is there are a lot of add ons. There's the case feeder, strong mounts, roller handle, bins and a few other odds and ends. Think it may have come to $750 total. I paid $900 for the used 1050, that's $150 more for a press that will run circles around a 650 and is cast iron.
If you're going to load rifle get the 550. I don't really load rifle on the progressive and still use a Rock Chucker. You just don't shoot a lot of rifle so I see no need of loading it on a progressive. Loading for an AR is another story. A progressive press excels when you need large amounts of ammo. For 50 to 100 cartridges you're wasting your time.
Don't think I covered caliber change overs with the Dillons.
The 550 takes maybe 10 minutes to change over, could be less if you keep the same size primer.
The 650 is probably 15 minutes and is a little more involved.
The 1050 is about 30 minutes to do a change over and that is not changing the primer size. However, I don't care what press you have, if we started at the same time, I could change the caliber on this one and probably pass you on ammo output within the first hour.
It would be great to find any Dillon or LnL used as I did with the 1050. But you just don't see them anymore. That tells me they move quickly. At one time I used to see them on Fleabay but anymore it's distributors selling new.
I would have no problems buying a used press and have done so. And I would do it again.
I also tend to agree about not priming on the press being counter productive. That is why I keep asking those that do not use the press why. More then anything I think they just got used to doing it that way. I have always primed on my presses without a problem or incident.