In the 1989 massacre of 14 women at the Ecole Polytechnique in Montreal, Marc Lepine used a Ruger Mini-14 rifle, at the time equipped with a substantial magazine.
And in 2006, Kimveer Gill used a Beretta Cx4 Storm to shoot 72 rounds at Montreal's Dawson College, injuring 16 and killing student Anastasia DeSousa.
Neither the Ruger Mini-14 nor the Beretta Cx4 Storm are prohibited in Canada, despite the outcry from victims and their families, the occasional political grumble, and a pointed coroner's report in Montreal.
The Ruger Mini-14 is also not restricted, and since the death of the long-gun registry last spring does not need to be registered outside of Quebec.
On the flip side, semi-automatic rifles such as the Ruger Mini-14 are widely used by Canadian hunters and in rural areas. Semi-automatic weapons can fire off rounds in quick succession without reloading, but unlike an automatic weapon, the trigger mechanism must be re-engaged each time.
"Firearms owners would say it's a matter of freedom. If we're going to restrict everything that has any possibility to do us harm, then the government's going to be pretty busy," said Alan Voth, a firearms forensics expert and retired veteran of the RCMP.
"It's not the gun, it's the person. Why would we want to go around chasing our tails, trying to chase something that is not the problem?"
Semi-automatics were banned in Australia in the wake of a 1996 mass murder in Tasmania. The United Kingdom has more stringent restrictions on semi-automatics than Canada, in the wake of its own tragedies.
"Australia is a safer country as a result of what was done in 1996," former prime minister John Howard wrote last August.
Prime Minister Stephen Harper defended Canada's gun control system in an interview with Quebec's TVA network broadcast Tuesday.
"First, the most important thing to remember is that Canada has a gun control system that is much more strong and strict than the Americans," Harper said.
"We will not change the basis of this system. Actually, we have reinforced certain parts. We abandoned the long-gun registry because it was veyr costly and there we didn't see any benefits, but we are keeping a licensing system for owners, a registration system for handguns and (restricted) firearms, and we will keep this system that works."
But some critics say the system has not screened out what are essentially combat-style weapons.
In the case of the Ruger Mini-14, dubbed the "poor man's assault rifle" by opponents, Lepine used 30-round magazines that are now banned in Canada. Today, the largest magazine allowed holds five rounds.
The Ruger Mini-14 was one of the weapons legally obtained and used by Anders Breivik to kill 77 in Norway last year.
Former Liberal justice minister Irwin Cotler suggested in a 2005 letter that he'd like to ban the Ruger Mini-14, but later said it was a "mistake" following opposition from Canadian gun owners.
The Canadian Association of Police Boards passed a resolution at its conference earlier this year to reclassify certain firearms, including the Mini-14, as restricted.
The Beretta CX4 Storm used in the Dawson shooting is a less powerful weapon, called a semi-automatic carbine, with a trigger that resembles one on a pistol. It is more compact than the Ruger, and the cartridge reloads behind the trigger.
Montreal coroner Jacques Ramsay said in his 2008 report on the shooting that semi-automatics such as the Storm should not be available to the public and should be prohibited outright. Gill was able to obtain one as a gun-club member.
"It's a lighter rifle, it's easier to manoeuvre, but it is still very precise," Ramsay said at the time.
Former public safety minister Stockwell Day mused in the days following the Dawson College shooting about restricting firearms such as the Storm, but that did not happen. The Ottawa Citizen reported 46 new registrations for that model of gun in the month after the shooting, compared with just 16 the month before.
Heidi Rathjen, one of Canada's foremost gun-control advocates, says she and others have not called for a ban on all semi-automatics — just some of them.
She says the federal government has not reviewed or updated its list of restricted or prohibited firearms since 1996, and many out on the market are basically assault weapons masquerading as hunting gear.
"Ban military assault weapons, ban weapons designed to kill people in combat situations for civilian use," said Rathjen, spokesperson for Poly Se Souvient.
"They haven't done that. In fact, they've gone in the opposite direction by ignoring new assault weapons coming on the market and allowing many of them to stay even unrestricted so they're not even registered anymore outside of Quebec."
But Voth says there really is no substantial difference between the Ruger Mini-14, and other semi-automatics that are used frequently by hunters.
Even the Bushmaster AR-15, restricted in Canada to gun club enthusiasts with tight licensing requirements, only looks more menacing than other weapons that are unrestricted, he says.
"The ability to do a lot of damage with a firearm exists even with something as archaic as the Old West double-barrelled shotgun, which is limited to two shots," said Voth.
"It's absolutely unbelievable how fast a skilled operator can shoot and load something like that and the number of shots they can fire in a limited amount of time. The difference between that and a semi-automatic for the purposes of mass murder is inconsequential."
The RCMP did not respond to a series of questions about restrictions on firearms.
Harper said during the interview with TVA that he was greatly affected by what he saw on the news out of Newtown, Conn.
"It's very sad. As a father, it's very difficult to watch these images of children who were killed," said Harper.
"Over the weekend, in the end, I stopped watching. It's almost impossible to imagine how someone could do something like that to children. It's a great tragedy, and we're using the opportunity to remind our children of our love."
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