Or you could buy this -
https://www.streichers.com/sig-sauer-p320-compact-9mm-threaded-barrel
https://www.streichers.com/sig-sauer-p320-compact-9mm-threaded-barrel
Sig customer service has the barrels or will allow you to back order them. Mine took about 2 weeks to get to me.Not in stock but I appreciate it. Besides, kind of like the idea of a factory barrel rather then aftermarket.