The attached video relates to the Canadian ban of the Ruger No. 1 single shot rifle. The loophole, if you want to call it that, pertains to firearms that discharge projectiles delivering over a certain amount of energy at the muzzle. We're not talking field artillery here or even .50 BMG but commonly produced firearms in calibers used to take very large, or very dangerous game, ie .460 Weatherby Magnum. The rifle manufacturer doesn't even need to have made the rifle in one of these cartridges, the fact that some person at some time built a rifle chambered for such a cartridge will do the trick and cause all rifles in that model to be banned. This is sort of like the BATFE ban on ChiCom steel core 7.62x39mm ammo in this country because someone once made a pistol chambered in that caliber.
Coming to a country near you --
https://www.youtube.com/watch?v=aYAha0XmfjY