From Gunsite.com:

"These forms and records are used by law enforcement agencies to trace firearms associated with crime. To initiate a firearm trace, the police must note the serial number of the gun, then forward a firearm trace request (Form 3312.1) with other pertinent information to the ATF. The ATF then contacts the manufacturer who identifies the wholesaler that bought the firearm. The wholesaler then refers the ATF to the retail dealer who, using the bound-book, identifies the original retail purchaser.

The ATF considers a trace successful if the original purchaser is identified. Normally at this point, the ATF turns the case over to local law enforcement, however in rare cases the ATF attempts to follow the chain of possession. To trace a gun beyond the first retail purchaser, law enforcement authorities must conduct interviews and use informants, and of course these methods are often unsuccessful.

It averages 11.4 days to trace a firearm to the first retail purchaser. The ATF has developed a computer system that reduces trace time to an average of five days. Participation is voluntary, and it is anticipated the number of licensees participating will increase. (ATF, Commerce in Firearms in the United States, February 2000, p. 20) "

This is for a standard firearm. Obviously, NFA is handled differently. That is why I asked what I did. Other than NFA there is not National Registry maintained by the Federal Govt. that I am aware of.