In NYS, as with the federal law, a rifle "qualifies" to be an "assault weapon" if it is semi-automatic and can accept a detachable magazine; accepting the magazine is not an "evil" feature itself. Once you have yourself a semi-auto rifle that can accept a detachable magazine, if it has 2 or more of the following features, it is an assault weapon:
1.) A pistol grip that protrudes conspicously beneath the action of the weapon
2.) A bayonet lug
3.) A threaded barrel that is capable of accepting a suppressor or flash hider
4.) A rifle grenade launcher
5.) A flash hider
6.) A folding or telescoping stock
If you have a post-ban AR- type rifle, it can have a pistol grip, but no other feature. Once you have 2 or more, your rifle is violating the law.
If however, your rifle or lower receiver was made before Sept. 14, 1994, it called a pre-ban, and can be loaded with all your favorite evil features. Don't be confused with vendors from other states who list their rifles and receivers as "pre-ban" on online stores and auction sites- they usually aren't. They mistakenly call their rifles "pre-ban" when they are actually "no-ban."