Re: Need to refresh my memory
Some of your approach, your plan, is tied to the cartridge.
Will the formed cartridge be different for the reloading brass? That is, are you going from 260 to 260AI, or 243 to 22-250(as an example)? Or are you just loading something like 25-06 to stay as SAAMI 25-06?
If you're not changing the design with initial forming, then just let the cases fireform to your chamber, and then reload it normally.
I don't count on un-fireformed cases to perform consistently. They hold capacity variance, and FL sizing of new brass won't help with this because fired brass is forever different than new brass.
So I consider the first shot of it to be wasted anyway.
For a first shot of new brass, you can just run a moderate load with cheap bullets seated long(to jam).
Now even though the brass isn't 'fully formed' at one firing, it's close enough if you're going to change it all with FL sizing anyway.
You probably won't need or be able to bump shoulders until 3-5 cycles.