Yes, Canada has border controls and customs inspectors... I honestly don't understand how this is controversial. It's fairly difficult to get a license to own

Yes, Canada has border controls and customs inspectors... I honestly don't understand how this is controversial. It's fairly difficult to get a license to own an AR-15 type rifle in Canada, the magazine is restricted to 5 rounds, and if you try to cross the border with one, you have a reasonable chance of being arrested. Once in Canada, if you take your American AR-15 to a shooting range, you'll be arrested. In the U.S., for better or worse, most anyone can buy almost any kind of gun they want. For someone that intends to shoot up a school, the prohibition on taking their legally acquired gun into the school zone is the least of the crimes they're committing.