The reason that registration existed in the first place was because it assured that the tax had been paid. If there is no tax there is no need for registration.2) The HPA and SHORT amendments to the bill which dropped suppressors, SB-things, etc. from NFA. Arguably a better deal than a $0 tax but it was MORE than JUST a tax change. It was a regulation change.
Also think about this: If they can get the registration language to stick, what prevents them from adding other firearms to the list of weapons that must be registered? The precedent is set.
No taxation but you have registration. They will argue, "You won't have to pay a tax on the guns you already own and we're not banning them. All we want you to do is register them." BOHICA!
Go back and read post #289 if you haven't already.