One way to look at it is that 10-round magazines are readily available. In the eyes of many, limiting handguns to 10 rounds doesn't place a huge imposition on gun owners. In places like New York, most folks already have them by default.
Now, switching to 7 rounds will require new manufacturing and tooling. Such a law will require people to dispose of or relinquish property they already own without compensation. Serious 5th Amendment issues abound.
Sorry Tom but I think you're wrong on this one. I think it'll stick just fine, and nothing short of doing an etch a sketch shake and wipe and replacing everyone from the governor down will get the magazine limit fixed in NY. I HOPE you are right, but I don't think so. Time will tell.
I'm still hoping that Christie will be smart enough to realize that if he wants to be president someday, signing stupid laws like this isn't the way to go about it. NJ is a already a bigger pain than it's worth.