They did the same thing in New York. Connecticut got around it by certifying the legislation as "emergency" -- even though the shooting was 3-1/2 months prior and there was no history or pattern of similar mass shootings in Connecticut for something like 350 years.
Basically, it just shows how broken the political system has become in the United States today, but that's a topic probably beyond the scope of this forum. The bottom line is that Connecticut has an emergency process to streamline the adoption of laws, and they used it here even though there wasn't any emergency. I guess anything is an emergency if they have enough legislators to vote that it's an emergency. (How's THAT for due process?)
The word I received in a brief e-mail from my friend at the CCDL meeting is that there will be an appeal in Federal court. Supposedly the NRA will be part of the suit, or backing it in some way. No mention of the Second Amendment Foundation. I had asked about a challenge in state court under Connecticut's state constitution. The response was that the legislature thinks they worded the law in such a way that it doesn't violate the state constitution. Since there is no state supreme court affirming a right to be armed with the "weapons in common use," that may be a valid assessment. Connecticut folks are still allowed to carry 10-round firearms, so their RKBA under the state constitution has not been eliminated.
I just hope the legal team in Connecticut is up to the task. It is obvious from several news reports I've been reading that both Connecticut and the Obama administration are hoping to export the Connecticut approach to other states. To quote our old friend Barney Fife, "We've got to nip it in the bud."