yeah, this is the first ive heard of it as well.
here is the part in question:
“Large capacity ammunition feeding device” means a magazine, belt, drum, feed strip, or similar device, manufactured after September 13, 1994, that has a capacity of, or that can be readily restored or converted to accept, more than ten rounds of ammunition; provided, however, that such term does not include an attached tubular device designed to accept, and capable of operating only with, .22 caliber rimfire ammunition.
and a few sites even have them for sale new to ship to nys
http://www.rimfiresports.com/merchant.mv?Screen=PROD&Store_Code=RSC&Product_Code=EAG2230