Using 375 Ruger cases, cut to 2.1"
Pushed a guided drill bushing with a 3T arbor press.
Then sized with a 458 die.
On the lathe, trim the belt to length and the base to diameter.

well, that's pretty cool

Do you rely solely on the radius of the mouth of the bushing to feed such a big case through?
This is really interesting!

A Ruger case has a shoulder of .515 the bushing starts over this easily. Then with one long push, it is sized. It works best with a full length case. I only have basic brass, so I cut it to length first and then tapered the mouth to fit the bushing.