It doesn't limit ammo at all.
It doesn't reserve that express right, either. It's meant to be dealt with by elected officials. Prohibiting large-capacity mags violates no Constitutional provision, and evidently the assualt rifle ban didn't either, although I'd disagree with going that far.
Wiley- Like I mentioned a couple posts back, the shooting was only 90 seconds. A few reloads in a stressful situation is less people shot at the end of the day. No, the outcome wouldn't have been drastically different, but it would have been different. Many people argue that the killer could have used homemade explosives with everyday items that you can pick up at your grocery store. However, he didn't. He chose the gun route. Had such a simple regulation been in place, he wouldn't have had easy access to large clips and the result would most likely have been different, as I've already laid out. Furthermore, not being able to shoot 100 round mags at a range is not even really a price to pay for legal gun owners.