In a worst-case scenario the pistols themselves would be outlawed. I don't think that will happen. The next most likely scenario is that there will now become a huge market for "crippled" magazines (my own term - but I think it is a good one). That would be a 10-shot magazine made for a firearm that normally holds much more (i.e. only the top part of the magazine would be funtional and the bottom part would simply be some kind of empty space or filled plastic).