I’ve got a Sig P229 & both the .357 Sig and .40 S&W barrels. Ballistics aside since either will do the job just fine, I shoot the .357 Sig significantly better than the .40 S&W. The .357 Sig seems to cycle much faster with less muzzle flip than the .40 S&W which keeps me on target for a faster follow up shot. My completely unscientific findings are that the .40 flips up more than I like in the 229 and the .357 Sig pushes straight back. The .357 Sig "in a P229" feels a lot like +P or +P+ in my P229 9mm.
Long story short, I carry the .357 Sig because I shoot it better. I still like the choice to use both. Especially when ammo supplies look like they do these days.
Long story short, I carry the .357 Sig because I shoot it better. I still like the choice to use both. Especially when ammo supplies look like they do these days.