Yep, Bad Idea the way I read it. Looks like anyone owning any firearm for which a federal purchase record cannot be located is in possession of an illegal firearm. Veterans (+heirs)appear to be the only ones who can legally "register" firearms acquired outside the US (or for which proof of purchase within the US cannot be produced, as in most private sales) and only if they do so in the 90 day amnesty period. This puppy smells so fishy it should be DOA and clearly impinges on 2A which contains no mention of where firearms must be acquired before being kept and borne. Neither does it limit itself to the "machine-gun" denominations which are subject to transfer tax and registration.
It sounds like the brain child idea of banning center fire ammunition in as much as the same lame 'thinking' is behind it.
There's at least three ways it can be interpreted to justify confiscations and worse for legally owned firearms.
This is a bad idea.
I'm also willing to bet that the 'amnesty' isn't.