I batch loaded for a couple decades. In a way, I still do... kind of. My time available for shooting changed radically a few years ago and I found myself with a need/desire to up my production some but continue to stick with my tight budget. To complicate matters, I have a whole lot of fun working in an array of calibers, so I wanted to find a balance of these four things:
1) quality
2) production
3) slew of different calibers
4) budget
At my bench, my own personal key to the quality of my ammo comes from metering my powder each round at a time and seating my bullets. I like/need to see a full tray of 50 charged pieces to ensure visually that the powder level is the same across them. I also love to seat bullets single stage so that I can get the feedback in my press handle, letting me know that I have the case mouth tension that I want and all of this (for me) adds up to high quality ammo that I have a lot of confidence in.
So I needed to find a way to speed up the resizing, depriming, priming and case mouth flaring operations.
I went semi-progressive. I picked up a used Lee Pro-1000 and started with 9mm. No powder handling, no bullet seating. I wanted to see if I could use the lowest-cost progressive on the market to prep my pistol brass.
With this machine, I am not only doing three operations with each full lever throw, I am handling brass a fraction of the time. I only have to drop a piece in one at a time and it moves between stages and gets kicked out in to a collection automatically.
Now, I can pile up a large lot of fully prepped brass. It is clean, sized, primed and the mouth is flared and it sits in a container until the day I want or need ammo. Just grab a container, drop them in to a tray of 50, use my Lyman 55 to charge each piece and my Lee Classic Cast to seat bullets.
Caliber changes for the Lee Pro-1000 are (by far, not even close) the cheapest on the market. For some changes, I only swap a turret (I paid $8 a turret) and I'm doing a different caliber. I use this machine across a dozen different handgun calibers. With my hybrid setup, my ammo is absolutely as good as it has ever been and I spit out around 20k a year this way. Been using this method since... 2011 or 2012?