N.Y. Environmental Conservation Law § 11-0931
1. No person except a law enforcement officer in the performance of his official duties shall use in hunting or possess in the fields or forests or on the waters of the state for any purpose: a. the apparatus known as a silencer; b. any automatic firearm, or any firearm which has been converted to an automatic type, or any firearm which has a built-in mechanical adjustment which will permit it to function as an automatic arm; or c. any auto-loading firearm of a construction to contain more than six shells in the magazine and chamber combined, except
4. a. No person shall: