I don't see that there's a necessary connection between "universal background checks" and gun registration. Depending on how the law is written, those two things can be entirely decoupled. That's where our input would become important. Will private sellers be able to access the NICS directly, or will all transfers have to be channeled through FFL's? My biggest worry about the UBC is economic. If all UBC's are channeled through FFL's, and they're allowed to charge whatever they want for the service, this could easily add $50 or more to the price of the gun. The price of used guns would have to be lowered accordingly, perhaps to the point where it's uneconomical to sell.