Brady Campaign on Assault Clips

From the blog Free North Carolina comes word of the Brady campaign's new initiative against hi cap magazines.

View the post with the Brady Campaign video ad here: http://freenorthcarolina.blogspot.com/2011/04/brady-campaign-on-assault-clips.html

I'm really curious what exactly an "assault clip" is as I've never heard of one before... is it like one of those barrel shrouds, with the shoulder thing that goes up? Regardless, I have a few ideas where they can shove their "clips" and this ridiculous legislation.