The point of magazine capacity restrictions is to change the relationship between government and the people. It has nothing to do with protecting innocents. By establishing the power to specify what arms a citizen may possess, a preexisting right not granted by, but protected and guaranteed by the bill of rights is transformed into a privilege granted at the whim of the sovereign ruler. This is a fundamental change to the philosophy of society set forth in the Declaration and codified in the Constitution.
It is similar to recent efforts to gut the freedom of religion and freedom of speech. It is also similar to efforts to gut the protections against illegal search and seizure and attacks on other parts of the Bill of Rights.
A massacre like Sandy Hook would have been well within the capability of a Legionnaire with a gladius. It would have been easy with any firearm since the earliest metallic cartridge repeaters, such as the Henry of 1860 or the improved Henry of 1866, the gun that won the Battle of the Little Bighorn.
I don't remember hearing about such school shootings by deranged young men in 1860, or 1900, or 1940. The difference is not the capabilities of the weapons. That is not something that has changed that much.
The recent mass shooting is being used as a pretext for the kind of power grab that can fundamentally change our form of government. It is a despicable exploitation of the victims that does nothing to protect others. It is disappointing that otherwise intelligent people are so naive and clueless as to not understand the underlying dynamic.