Welcome to the forum Forrest! I am a fellow Sig owner (P229 9mm) but I know that for your P239, you can get a .40 Sig factory barrel and just drop it in. I'm not sure about 9mm but I think there might be some aftermarket ones out there that would fit, not sure though. One thing I'm sure of is that you'll enjoy that gun! Never shot a P229 but I've never heard bad things about it either! Feel free to ask around if you have any questions!