Here is an interesting article I found online. It seems to explain the complex process a little better.
<span style="color: #3366FF">Laws make gun trail tracing difficult
By Mike Wereschagin
Sunday, September 30, 2007
A slip of paper stood between Robert Bigi and a gun used in a shooting across the state line in Maryland.
In 1998, Bigi, 70, of Fayette County, sold the semiautomatic pistol. He provided record of the sale to Pennsylvania State Police, as state law requires when a handgun changes hands.
In spring 2005, Bigi received a call from a Cumberland, Md., sheriff's sergeant.
"He says to me, 'Do you own a semiautomatic Makarov pistol?'" said Bigi, a member of Firearm Owners Against Crime.
The pistol had been used in a domestic dispute in Maryland. A gun trace by the federal Bureau of Alcohol, Tobacco, Firearms and Explosives turned up Bigi's name.
The paperwork proving Bigi sold the gun never left Pennsylvania. That wasn't an accident. State and federal laws prohibit law enforcement agencies from keeping comprehensive, up-to-date databases of gun owners.
The laws are intended to prevent government officials from knowing what kind and how many guns a person owns. Those same laws require a record of every gun sale to be kept by the seller. It's a system designed to be fragmented.
Investigators say these laws force them to trace each gun, an unreliable process that can take weeks and divert resources from an investigation. Gun rights advocates, however, say making it difficult to trace a gun is better than the alternative -- a national registry containing dossiers on law-abiding gun owners.
Maryland authorities found Bigi through the ATF tracking system, which by law can find only a gun's first owner. After that, police must follow the gun's trail by interviewing or requesting records from the gun's succession of owners.
Bigi was the hand-off between the ATF and the Maryland sheriffs.
A meticulous record-keeper, Bigi made copies of everything he gave to the Pennsylvania State Police, and offered them to the Maryland sergeant. If he hadn't, the sergeant told him, he would have been subpoenaed, Bigi said.
Even after the call, Bigi doesn't favor the sharing of gun ownership information between states. Instead, he said, authorities should share more criminal records -- such as protection-from-abuse orders -- and mental health records.
Transferring gun ownership records between states would create the sort of national registry that worries privacy advocates.
"That's (gun owners') biggest fear -- the government knowing who has each and every gun," said Republican state Rep. Robert Godshall of Montgomery County.
Godshall wrote the law banning a Pennsylvania gun registry, which passed during the 1995 special legislative session on crime. Gun owners cited the law in a 2000 lawsuit, saying the state police database of handgun sales constituted an illegal registry. Commonwealth Court Judge James R. Kelley wrote the majority opinion in 2002, siding with the state.
The records are used "as a starting point for investigators when a handgun used in a crime is recovered by police," said state police spokesman Jack Lewis.
Though records don't cross state lines, guns often do. The ATF tried to trace 9,092 guns found in Pennsylvania in 2006. It succeeded in finding the original owners of 5,607 of those guns. Among those first owners, 1,200 were from out of state, according to the bureau.
How the handguns crossed state lines -- federal law bans interstate handgun sales -- is a mystery that has to be unraveled one gun at a time, and only if local police invest their own resources.
"Once we trace the gun to the initial purchaser, the record -- the paper trail of that gun -- ends right there," said John Hageman, an ATF spokesman. The 1968 Gun Control Act, the same act that outlaws interstate gun sales, prevents the ATF from tracing past the first purchase, he said.
The federal act requires gun dealers to keep records of any guns they sell, however, and gun rights advocates say that's enough for police who want to trace a weapon, even in states that don't maintain a sales database like Pennsylvania's.
"When a handgun is purchased at a sporting goods store, a record of that sale is there. It's open for police protection, and it's there as long as that store is in operation," Godshall said.
Investigators say a registry would save time spent tracking down gun owners and requesting records from gun shops across the state and country.
"It can be upwards of a couple of weeks, depending on how recent the sale was, or even longer," said Pittsburgh police Sgt. Mike Tracy. "It bogs down the system, it slows down the investigation. We have to do a lot of interviews, exhaust a lot of different avenues," often only to learn the gun was stolen.
"We just have to work around it," said Capt. Bret Waggoner, director of special investigations in the state police Bureau of Criminal Investigations. "The only thing you can do is go back to the original purchaser. You go back, you interview him. 'Tell us what you did with that weapon.' But he's not obligated to tell you."
Tracking guns isn't an effective way to catch criminals, said former Marine Kim Stolfer, firearms instructor and chairman of Firearm Owners Against Crime.
"If those people who address this are asked a question -- prove how this is going to help -- their approach falls apart," Stolfer said. "When you boil it all down, it does not do anything but distract the administration of justice from pursuing the ... criminal. I'm not saying they shouldn't do it, I'm just saying there are" more effective tactics.
Those tactics include making sure prosecutors squeeze the maximum possible sentence from gun crime convictions, and lowering recidivism rates to reduce the number of repeat offenders, Stolfer said.
"The shallowness of addressing the complexity of this problem is sometimes disturbing," Stolfer said.
Laws make gun trail tracing difficult