It's been an expensive experiment.  Very expensive.  What the anti-freedom people claimed would only cost $2 Million (Canadian) is now $2 Billion (Canadian).  Read the timeline here of the failing gun registration scheme.  It may even bring down the liberal government.  A snippet follows:

Jan. 7, 2004

Prime Minister Paul Martin says the gun registry is under review. "We are committed to gun control and we are committed to the registration of weapons, but at the same time, common sense dictates that there have been a number of problems," says Martin. "They will be looked at and dealt with."

Feb. 13, 2004

Documents obtained by Zone Libre of CBC's French news service suggest that the gun registry has cost $2 billion so far.

May 20, 2004

The Liberal government, just days before an expected election call, eliminates fees for registering and transferring firearms. Ottawa will also limit its spending on the gun registry to $25 million a year, spending which has averaged $33 million a year and reached as high as $48 million. Licensing of gun owners and firearms will continue.

The problems they speak of are, in a large part, due to the resistance of the gun owners.  Any American politicians considering gun registration in this country should keep in mind the U.S. has far more gun owners who will put up far more 'resistance' than the Canadians.