From NRA-ILA:

We would like to make our position clear.  The NRA strongly opposes ANY expansion of the Undetectable Firearms Act, including applying the UFA to magazines, gun parts, or the development of new technologies.  The NRA has been working for months to thwart expansion of the UFA by Senator Chuck Schumer and others.  We will continue to aggressively fight any expansion of the UFA or any other proposal that would infringe on our Second Amendment rights.