I've talked to a few different Sig reps and they all said that the P250 SC .357sig barrel shouldn't be used in the P320. They said that the SC barrels aren't cross platform compatible like other sizes. I found that very odd and even after more questions, they all said to wait for the P320 SC barrel and not buy the P250 one.I just ordered a .357Sig barrel in subcompact for a P320 (P250) that I haven't even bought yet. Sig said they had 4 in stock, thought I might want to get one before they are gone since the P250 (same barrel) has been discontinued. I love the .357Sig round. I don't know why you can't buy a subcompact chambered in .357 from Sig, but at least the P250 barrel works in it. I have to practice "but honey, I already bought a barrel for it, you have to let me get the gun". Lol, she is very understanding and won't mind a bit, she knows I want to get one, she likes them too! I'm thankful I got a .357Sig barrel for my discontinued P224. Happy St. Patricks Day.
I'm the first one to take anything a Sig rep says with a grain of salt. Most of the time you get answers like ... 'well you really shouldn't' or 'I really can't confirm that'. That normally translates into, it will work but the layers won't let me tell you that. This time it was a flat out no.
I have a .40sw SC X-change kit that I already have a 9mm barrel for and am waiting for the 357sig. I much prefer 357sig, but I don't mind waiting. The 9mm makes easy range time