The AR-15 and all variants are specifically named as restricted firearms. It is how the Liberals wrote the Firearms Act back in '94-'95. It is generally agreed that those idiots knew so little about acutal firearms that somebody physically left a conference room, when to a magazine stand, purchased the latest copy of the Guns Annual Buyer's Guide and they all crowded around picking out the "scary" or "evil" rifles.
Those rifles were specifically named.
Thankfully, the Liberals were so incompetent and so short-sighted to realize that there were dozens of other designs in existence that didn't make it into their magazine to cherry pick. They also didn't take into consideration the invention/creation of completely new designs that didn't exist in 1994-95. As a result, as long as the firearm in question isn't specifically named, has a long enough barrel/overall length and doesn't have the capacity to fire full auto/burst, it can legally be imported into Canada. The RCMP have tried some unilateral re-classifications, but NFA and CSSA have quashed that trend, with the exception of the T-97 and Krinkov VZ situations that will probably end up in court, if the bureaucratic idiots responsible will ever allow the red tape to be cut through to permit the importers their day in court.
In reality, it makes absolutely no logical sense to restrict these rifles. They pose no greater danger to the public than any other semi-auto hunting rifle from Browning, Ruger or Remington. Check out the last issue of the NFA's Canadian Firearms Journal, they did a center spread story on this very issue. In the US the NSSF is also running a similar campaign.
If you want to use this rifle in the field, start writing letters. We get enough average gun owners, hunters (both new and old) and the black rifle guys active, and who knows what we can accomplish.
The rifle was almost prohibited, if not for the intervention of the DCRA and pro-firearms rights groups like the NFA who appeared before parliamentary committees to argue for the sporting value of the AR-15 in terms of use for Service Rifle competitions under the auspices of the DCRA and provincial rifle associations. We effected real change then, why not today? We'll never know unless we try.