When it became clear that the Federal AW ban wasn't likely to be renewed (several years back), the main anti-gun senators, who are mostly from anti-gun states, pushed to pass a state version of the AW ban which would never expire.
The PRK was the first such state, but NY and a few others have passed similar laws.
For PRK residents, nothing will change with the expiration of the Federal AW Ban except that those folks who have *registered* post-ban guns will be able to put them into pre-ban configuration.
-Troy