No, the 9mm won't feed. But you can feed .380 in a 9mm. Bad idea. Always double check your ammo and weapon. And don't assume your wife grabbed the correct box out of the truck.
/john
What happens? Will it scar the barrel or worse? Curious as I currently have 9mm and I still have a couple boxes of .380 sitting around.
While I asking questions, how do you discard safely ammunition you can not use?