Colorado has a 15 round limit on new magazines sold in this state. Magazines acquired before 1 Jul 2013 are grandfathered and since Mags don't generally have their birthdate marked on them, and since repair kits are not magazines, there is a healthy trade in repair kits. It also helps that most of the county sheriffs have stated that they have better things to do than to go about inspecting magazines.
The magazine law is certainly an infringement on the second
amendment, and like all gun laws, redounds to the benefit of the
criminal class rather than providing any protection to the law abiding.
As we also know, judges are impartial, and supreme court judges only
take into consideration the constitutionality of a statute without
regard to any other considerations.
So what are the odds this law will be struck down or limited in any
manner at all? I'm putting it as somewhere in between the appearance of
flying pigs and the second coming of Jesus Christ.