There are some really significant differences between gun laws & gun crime in Canada and the US - in fact - between the US and almost every other "Western" nation:
https://en.wikipedia.org/wiki/List_of_countries_by_firearm-related_death_rate
In particular, the largest difference is the NRA and their interpretation and political/legal pressure in using the Second Amendment to the United States Constitution (the right to bear arms - any and all arms) is what makes any assumptions that gun legislation & use in Canada is equal and equivalent to that in the US - both naive and wrong.
Unlike the US - where the right to bear arms is constitutionally protected - there have been many successive changes in the gun legislation laws in Canada over the past 40 years or so.
Much of those safety-related changes (criminal record checks, safe storage, etc.) predate that of the so-called Lepine massacre - but that terrible and unfortunate tragedy was used - as were the victims families - to facilitate a number of predatory political and ill-supported changes to all firearms in Canada that had no basis in actually addressing public safety needs. No need to actually look at crime stats and holes in the so-called mental health services if you wish to make political gains - especially in Quebec - where the shooting took place.
Part of that particular round of gun legislation changes included the expensive, oft-despised and now defunct long arms registry that came in just before a federal election and spearheaded by Federal Liberal Justice Minister Allen Rock who used the Quebec gun control advocates to springboard his reelection - as did other largely federal Liberal politicians - while ignoring the more rural parts of Canada who had minor political pull due to meek electorate numbers.
A very high number of Canadians (population numbers) live in the Quebec City to Windsor Ontario corridor. If the federal government panders to their urban needs - they acquire a high number of votes to get reelected in Canada. Quebec, in particular - has a huge effect in elections - especially if you are a federal Liberal and/or Bloq. If you want to form the Canadian government as a federal Liberal - you need Quebec - otherwise they vote for the Bloq and maybe separation.
There are still many parts of Canada that are truly rural verses urban.
In those areas, particularly - a gun (aka "long arm") is yet another life tool - like a chainsaw, an outboard, a fishing rod, or a a set of winter tires.
There has never been any evidence that this particular tool and life style (long arm and rural needs) was a significant issue that needed addressing in regards to decreasing gun crime in Canada - even after the Lepine massacre. I don't believe that the same could be said of mental health needs, or assault weapons, or gang violence.
It was however, a long-hanging fruit that the politicians could and did use for their advantage in temporarily appeasing both gun control advocates out of Quebec, particularly - where the Lepine massacre occurred - and the control freaks whom reside in the upper echelons of the RCMP. We are now - again - in that same situation - with a federal Liberal government trying to appease gun control advocates out of Quebec - by constructing the Liberal Firearm Committee and appointing Nathalie Provost to sit on the committee.
There has never been any indication that the long arms registry did anything other than waste billions of dollars in appeasing those groups. Money that would be better spent on the mental health system, IMHO.
Some pretty significant differences between Canada and the US wrt gun laws:
https://www.cnn.com/2017/07/19/world/us-gun-crime-police-shooting-statistics/index.html