For an AR-15 you can just use an AR Maglock and Kingpin, then it's just a button press to very slightly separate the upper and lower receiver, allowing for magazine ejection. It's almost as fast to change magazines as in other states.
There's also zero chance a criminal would follow these laws. It takes maybe a minute to disable a maglock and swap on whatever stock you want. "Freedom Week" or old 30 round mags are prevalent as well.
Interesting. Not sure if it is at related, but this made me think of the singularly before the Big Bang.