Depends on the provisions.
You think there's a panic buy now? If it passes, private sales will disappear, as everyone will hold what they've got. Supply and demand will cause prices to go even higher, peaking right before implementation.
Afterwards, it will depend on the provisions in the bill. Their value, as Martowski says will be both zero and limitless, if there's a no transfer provision. If they are declared NFA, their value will be high, not quite like full-auto, as the supply is much greater. If it is similar to the last one, prices will settle higher than now, but be stable.
PS: off topic, but JK if you're an originalist, how can you be a democrat?
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