Until 1985 it was a criminal offence under the Lord's Day Act to fire a gun on a Sunday. Pierre Elliot Trudeau changed that, not with a bang, but with a signature on the Canadian Charter of Rights and Freedoms.
Conservatives can take pride that they helped stamp out the waste of money that was the repressive gun registry (though scrapping it only wasted more public funds), but gun owners should remember that it was Trudeau's Liberal government that had perhaps the largest impact on easing restrictions on the use of firearms.
In 1906 the Canadian Parliament passed the Lord's Day Act, it was legislation designed to keep Sunday holy by prohibiting certain actions, such as stores being open and the shooting of guns.* This law was in effect and enforced until 1985 when the Supreme Court of Canada struck it down in R v Big M Drug Mart for infringing on the fundamental freedom of conscience and religion. Something the highest court could never have done if it wasn't for the Charter.
Of course since gun owners are more likely to vote Conservative, they won't be too persuaded to believe that Trudeau helped them more than Stephen Harper. But the fact is, Harper, in axing a registry, is nothing compared to Trudeau who was ultimately responsible for repealing the ban on firing a gun on 52 days of the year.**
* From the Supreme Court's description of The Lord's Day Act:
Section 5 provides that any worker, required to work by an employer operating on Sunday in conformity with the Act, be given a substitute day of rest; s. 6 prohibits any games or performances where an admission fee is charged; s. 7 prohibits any transportation operated for pleasure where a fee is charged; s. 8 prohibits any advertisement of anything prohibited by the Act; s. 9 prohibits any shooting of firearms; s. 10 prohibits any sale or distribution of a foreign newspaper.**Though a few provincial governments have since independently restricted hunting on Sundays, carefully citing the need for animal preservation and not for religious purposes