I have a player asking about shock lock breaching type rounds (and an underbarrel shotgun to fire them, but that's another topic) and wanted me to come up with stats. I'm thinking something along the lines of explosive or APDS, but treat as explosive in contact while removing the penetrating weapon rules. Make them only for shotguns.
That should make a nice dent without giving them more power against non-barrier targets. What say y'all?