I agree with both responses above. I made 375 WAI brass out of 30-06 brass by opening up to 416 then back down by sizing a little at a time - 8mm, 32, 338, 35, 375, 416 then back to 373 (I needed to go up and back down to get the shoulder right.)

But since then I've used 35 Whelen brass to 375 and then COW

I didn't need to anneal, but it is a very good idea, I think.

I prefer classic.
Semper Fi
I used to run with the hare. Now I'm envious of the tortoise and I do my own stunts but rarely intentionally