Legality also depends on where you are.
Try buying ammunition in Canada IRL, for instance. Big difference here than in the USA, I bet.
In the USA, it's as simple as going to walmart or farm and fleet for those in the midwest. not to mention you can get ammo online, or in any range where you shoot. How hard is it in Canada to get ammo?
You
can buy it at Canadian Tire (A major hardware store chain), but you have to provide something like three or four forms of IDs, of which there must be a firearms permit and possibly your registered firearm paperwork just to buy a box of ammo.
And a few conspiracy theorists that I know wonder just how closely tied the purchasing system is with the firearms registry. If all you have registered is a .22 rifle and a 12-Gauge Shotgun, the RCMP might be knocking on your door when you start buying a few boxes of .303 British Service (One of the most common hunting rifle cartridges in Canada.).