IMO ammo or magazine limits are just an underlying medium for complete gun confistication.
first we had no restrictions, then we had magazine capacity limits of 10 rounds. Now NY has set an example of a limit of 7. What do you think will happen when the next tragic event happens (because the restrictions will not work or prevent)?
If we let them limit our magazines, ammo capacities it lets them gain "proof" that guns are still the problem. Its a stepping stone for complete removal.
lightweight, cheap, strong... pick 2