Has nothing to do with detachable. It’s when it has the ability to accept a mag that is the problem. If that setup would allow you to break open the rifle and drop the mag, then only be able to insert or accept a new mag while the rifle is still open it would be legal. Unfortunately that system allows the rifle to be closed without a mag in place and allows it to accept a mag when closed. If they could engineer around that it would be good to go.MarineCpl pretty much nailed it. The magazine is detachable, full stop. Doesn’t matter whether you need to press a button to break open the rifle to do it.