Magazine capacity bans, do they do what they're promised to do? Will they slow down mass shooters? Will they give victims a chance to tackle a shooter during the reload? Will they make anyone safer?
In a word, no. And here's thorough proof. (The text is a little slow in the beginning, but stick with it).
It even shows how a 6 round revolver can be emptied just as fast as a 15 round Glock.