In Canada's defense, that is in significant part, handguns. If you keep a long gun with you, as long as it doesn't hit their 10,000 J (7375 ft-lbs) muzzle energy limit

and if it's in your glovebox, I assume that whatever you have isn't doing that

and doesn't hit their specific restrictions on upper receivers, you're probably okay.

A NATO 5.56 mm rifle round looks like it has a muzzle energy of about 1.8 kJ.

That'd let you carry an elephant gun.

If you want a semi-auto rifle...goes looking

Looks like they exist in 500 Auto Max.

https://gunsamerica.com/digest/big-horn-armory-ar500/

I imagine that one of those would be okay. Looks like the ammunition is sold in Canada.

EDIT: If you want something that you can shoot one-handed, maybe a short bullpup rifle with a barrel of at least 470mm (~18.5 in), which is apparently their "handgun"/"not-handgun" divider.