I`m just curious about this. I don`t have any guns I can do this with and I certainly wouldn`t if I could,ahem. It concerns the legality of loading a post ban 10rd. mag with smaller caliber rounds that will allow it to hold more than 10rds. without modification. Example, some guns use the same mags for 9mm and .40 (Astra A-75 for one) and function fine. Maybe some others will too (maybe not). If that`s the case,what happens if you can load say 14rds. of 9mm into a .40 10rd. postban mag,it functions fine and you use it in a 9mm pistol. Does that make it an illegally modified post ban mag even though it`s unmodified? What if you have to tweak the feed lips a bit to get it to run in 9mm? Is it only illegal *in* a 9mm pistol and or when loaded with more than 10 9mm rounds? This is of course purely theoretical. Marcus