Harris
Welcome...
You shouldn't arbitrarily skip steps.
Cases should be trimmed if they are too long.
I'd suggest measuring a good sample of your cases and check their length after re-sizing. You're new to this.....It's good for you to know any way.
If they are not too long, then they don't need to be trimmed and you're still "by the book"

Maybe someone who reloads the 40 cal can offer you tolerances.

After measuring 9mm and 45 ACP cases for awhile, I've found they do not need trimming.

I do however trim all my 357 cases to 1.280" and keep my 357 dies locked down for uniform crimps.

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I'd like to agree with you BUT