New brass

I have buckets of my own ‘picked up’ brass mixed with range pickups. For my first go-around with 10 mm I want to use new brass, so I bought Starline, since that’s what they had at Scheel’s (the Hornady brass was out of stock).

Do I need to prep brand new Starline brass? Size? Trim? Or just stuff the load?

I have Hornady 155 gr XTP bullets. I’m thinking 10.8 gr of HS-6 (but I also have Power Pistol).

Suggestions? Does new brass need to be ‘prepped’?

If it were mine, I would size but not trim. Never known pistol brass to need trimming, but sizing would ensure the rest of the process started on the right foot.