When will they reopen the federal machine gun registry ?

What would it take to have the federal machine gun registry reopened and will it ever expire like the assult weapons ban did in 2004. And how long after it reopens will someone beable to buy a slect fire weapon for a reasonable price simalar for what you can buy a semi auto rifle or the same kind for. Also would you still have to get a class 3 lissence to get a full auto and pay the $200 NFA tax. And are they any talks in congress about lifting the ban. Thanks