The "US" isn't everything that Canadian's think it is...
In the US they have what's called CLASS III firearms. These were created (essentially) if memory serves me right in 1934 by the NFA (National Firearms Act) and includes everything from full auto machine guns to short barrel shotguns and short barrel rifles. Any rifle with a barrel under 16" is a CLASS III firearm.
These aren't exactly prohibited but they are highly restricted. First, you have to pay a $200 tax stamp to own one (it's for each gun). Next you have to be approved by the Federal Governement to buy each CLASS III firearm you want (usually takes a few months for each application). Most important you have to live in a State that allows you to possess CLASS III firearms (not all States allow this).
The Americans can't believe when I tell them that we have all the 7", 10.5" 11.5", 14.5" AR's we want and there's no difference between a 7" AR and a 24" AR in this country. They get around it by having what are classified as AR Pistols.
But to have a legal AR pistol it has to be manufactured as an AR Pistol (the receiver) and you can't add a stock, etc. to it. The moment you put a stock on an AR pistol or add a vertical foregrip to it you've created a CLASS III firearm and committed a felony.
This is the same for a handgun. If you take a Glock and put a foregrip on it you've created a CLASS III firearm and comitted a felony unless you first applied for a CLASS III registratio for the gun and paid the $200 tax stamp.
Their laws are as screwed up as ours. Some stuff may be nice (I agree) but some stuff really sucks.
Mark