Does Size Really Matter?

There are some uninformed elected officials in Congress that have set their sights  on magazines that hold more than X number of rounds (at the moment they are at the number ten).

The question is this: Does size really matter?

How long does it take you to change a magazine in your pistol or rifle? The answer varies a little bit between weapons, but it can take as little as 1 second, and up to about 5 seconds. So does it really matter about high capacity mags?