S&W factory 9mm barrels slug at .357 so no loss in accuracy. TK does excellent work.
Factory 9mm ammo gets light hits and tons of bullet creep in my factory 9mm S&W 929.
Here's a direct link to high res pictures
https://i.postimg.cc/DZSQsbDZ/IMG-20230921-193903163.jpg
https://i.postimg.cc/GtYkgnbn/IMG-20230921-193908279.jpg
https://i.postimg.cc/1tbGK3hK/IMG-20230921-193913466.jpg
https://i.postimg.cc/MGPbvY9N/IMG-20230921-193918688.jpg
I've got a 617 that spits lead, and is filthy to shoot. I also have a 1960 M17 that doesn't.
I bought a little tool to check the forcing cones, before I send it in for gunsmithing.
Here's the tool
Here's the M17