Canada has ~1/4 the firearms per capita compared to the US. My guess is that doesn't matter, as you go over 1 gun/resident the added guns probably don't have much of an impact.

However, most shootings in the US are with handguns (restricted in Canada), and a bunch of high-profile shootings with ARs (prohibited in Canada). Concealed carry is practically never allowed, and open carry isn't either. Safe storage is required, so you can't carry unsecured guns in your car either. Storing loaded firearms is forbidden. Owning firearms for self defense is forbidden by law (using them as such may or may not be, depending on the circumstances).

TL;DR: it's not just how many guns, but also what you're allowed to do with them.