Canada has fewer guns per person than the US, but still many more than most countries. I think there are a couple of other differences though. The types of guns are very different. Handguns are extremely restricted, and ownership is rare. Many (most?) semi auto rifles are either prohibited or restricted, and there are mag limits (5 rounds) for all centrefire rifles. This doesn’t exactly prevent people from committing shootings, but a lot fewer people have those types of guns because they’re kind of a pain in the ass get, store, and use. Safe storage is legally required, and much more encouraged by the gun-owning community.
The other factor might be what guns are used for in Canada. Concealed carry is practically non-existent, open carry is severely restricted, and while self-defence with a firearm is technically legal, ownership for that purpose pretty much isn’t.