As I understand it
First off, let me say that I don't own a progressive. But I have watched the process with .45 ACP rounds, so I understand how it works.
That said, as I understand it, no rifle sizing dies are made with carbide. Therefore, all rifle cartridges must be lubed prior to running through the dies, to keep them from sticking. Since the lubing process is manual, each cartridge must be hand processed through the sizing die. Post sizing, they should then (started to say: must) be measured and possibly trimmed. Only at that point can they be run through a progressive press for the benefit of the speedier process.
Me, I don't reload enough rifle rounds at a sitting to worry about it, but I do know some people who reload .223 on their progressive. Not sure what their total process is, just that their final rounds come off of the Dillon 650.
Remember - I said "as I understand it" regarding carbide rifle sizing dies. If anyone know otherwise, I'd be happy to know it. Hand lubing is messy.
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Looks like Snuffy responded while I was typing my original response. Snuffy - Do you do the whole process on the progressive, and if so, do you have to split it into three parts (sizing, then hand trimming, then progressive loading)?