AFAIK this is the current law in NYC concerning rifle mags:
10-306. Disposition, purchase and possession of ammunition and ammunition feeding devices.
a. No person, except a dealer in rifles and shotguns, may dispose of to another person an ammunition feeding device which is designed for use in a rifle or shotgun and which is capable of holding more than five rounds or rifle or shotgun ammunition, except in the manner provided in this chapter for the disposition of assault weapons, provided that a person in lawful possession of such ammunition feeding devices may dispose of such ammunition feeding devices to a dealer in rifles and shotguns. No dealer in rifles and shotguns may dispose of such ammunition feeding devices except to a person who is exempt from subdivision a of section 10-303.1 pursuant to section 10-305.
b. No person may possess an ammunition feeding device which is designed for use in a rifle or shotgun and which is capable of holding more than five rounds of rifle or shotgun ammunition, unless such person is exempt form sub-division a of section 10-303.1 pursuant to section 10-305, provided that a dealer in rifles and shotguns may possess such ammunition feeding devices for the purpose of disposition authorized pursuant to subdivision a of this section.