I think they are addressing something about clip capacities. As when an assailant is changing clips that;s a few seconds an armed guard or police officer can gain an advantage on the guy.
I don't see the slippery slope here.
I may be naive, but I feel there is no correlation between HCAW and typical hand guns.
Handguns serve a legitimate purpose, whereas HCAW do not.
I am sure if/when legislation is passed, many on the left will try to push even harder for more gun control, figuring the ball is already rolling, but I don't think they will have much success.
I agree that some are over-reacting, or using Sandy Hook as a tool to further their agenda, or both.
But there are many others of us who are not anti-gun, but also see a need for changes in the way the system currently operates.