You CAN buy a mag from another state so long as it is pre ban. The problem is knowing if the mag was made pre ban or an unmarked after "sunset" (end of the ban) mag. I looked into this because I want to buy a few BHP 13rd 9mm mags.:banghead:
It is a class D felony to manufacture, transport, dispose of, or possess a large capacity ammunition feeding device, which N.Y. Penal Law § 265.00(23) defines as "a magazine, belt, drum, feed strip, or similar device, manufactured after September thirteenth, nineteen hundred ninety-four, that has a capacity of, or that can be readily restored or converted to accept, more than ten rounds of ammunition." Section 265.02.