My barrels slug at 0.3549" to 0.3553".
And, the .357" bullets don't slide into my fired 357 Sig case mouths (like the .355" bullets do).
I guess I could make a casting of my chamber throats to see how much clearance I have. But, that means I would REALLY need to pay attention to brass thickness at my various case mouths for any reloads using .357" bullets.
I am really just thinking about swaging-down Gold Dots to get a bullet with a cannelure for my 357 Sig. I don't THINK I would get "jacket" rebound with those because they are really plated, so the "jacket" is less springy and is bonded to the lead. The way those bullets are manufactured involves multiple swaging steps after the plating process. I would just be adding one more.
I really don't like lead in high-pressure auto-loaders.
I do have a cannelure tool. But, my past experience with it is that it can bulge the bullet on either side of the cannelure, potentially leaving me with the need to swage that bulge back down again to avoid chambering problems and perhaps "bullet pinch." Hence, the question about swaging is still pertinent, even with the tool.
SL1