Right now (key words here)) I don't see the benefit in registering an AR as a pistol since Section 4 in Article 72 still covers it.
4. Magazines designed for one firearm but used in a different firearm
The maximum permitted capacity of a magazine is determined by the kind of firearm it is designed or manufactured for use in and not the kind of firearm it might actually be used in. As a consequence, the maximum permitted capacity remains the same regardless of which firearm it might be used in.
Example:
The Marlin model 45 (Camp Carbine) rifle chambered for 45 Auto caliber uses magazines designed and manufactured for the Colt 1911 handgun, therefore the seven round and eight round capacities are permitted.
Now here is what I see happening in the future:
1. RCMP renegs on it (they did happen to remove the LAR15 example from the article so it appears they may be doing that).
2. They will then work their magic in that once a rifle always a rifle so converting an AR over to a pistol won't work or you will not be able to use the AR with anything resembling a stock and if you have a brace it better not touch your shoulder.
3. They will pull a Butler Creek and make all LAR15 style magazines have to be pinned to 5 rounds
or
The govt puts in legislation the above.