Smee from what I read they can keep the mags of up to 10 rounds if they submit the paper work to register them. Only exceptions are Curio and Relics. Those must be registered. Loading them with more than 7 rounds is a felony. All mags that were of greater than 10 rounds that were owned pre 1994 that were registered are on deadline of being illegal. They must sell, destroy, or pemeanantly modify them to where they can only hold 7 rounds without it being able to be changed back.
So it looks like those that obeyed the law to register thier mags are now on the could end up being fellons if they do not comply with the new law list.
It is a very sad day for the law abiding gun owners of New York.
Also now to buy ammo in New York one must go through an NICS background check for any ammo purchases.
No matter how many times you do it and nothing happens it only takes something going wrong one time to kill you.