[kidcoltoutlaw]

When it comes to hot loads in the 357 SIG and the 40 S&W ?

[Jim Watson]

I don't know about Sig-Sauer.
One 'smith said he was sorry when Barsto changed from 410 to 416 stainless because it reduced the safety margin for 9mm Major ammo, before USPSA banned it.

If you are loading so hot that barrel material is a concern, you are loading WAY TOO HOT.

[JNewell]

I don't know, but I doubt that actual strength is meaningfully different between the two. Bigger issue is probably how the chamber is cut, both in terms of overall size and in terms of how well the case head is supported, but I have no actual knowledge whether they differ.