According to the CFC website when searching for "folding stock," we come up with this:
http://www.cfc-cafc.gc.ca/factsheets/r&p_e.asp
Definition of a Restricted Firearm
According to the Criminal Code, a restricted firearm is:
- a handgun that is not a prohibited firearm;
- a semi-automatic, centre-fire rifle or shotgun with a barrel length less than 470 mm (18.5 inches) that is not prohibited;
- a rifle or shotgun that can fire when its overall length is reduced by folding, telescoping or some other means to less than 660 mm (26 inches);
- any firearm prescribed as restricted (including some long guns).
So to the LETTER OF THE LAW, adding a folding stock to a non-restricted M1 Carbine and reducing the length to under 26" will require you to call the CFC to re-classify it as "restricted." So if you're looking for a range only rifle, or a rifle to keep in a collection in your home, by all means slap on the folding stock, call the CFC, re-classify it at restricted, and you're set. Or, if you actually want a rifle you can actually take hunting, shoot at your private range, and will actually have decent accuracy with a full wood stock, enjoy your M1 Carbine as is. Again, speaking by the LETTER OF THE LAW, if you don't have an RPAL and you slap on a folding stock and the gun eeks under 26", you're breaking the law, and you're giving the Lieberals and Anti's another reason to further narrow our sport/hobby/passion.
If the M1 Carbine is already restricted, have at it. It won't change the classification at all, and you already own the rifle and you already know your limitations on where you can use it. For you, a folding stock makes no difference.
If you're looking to waste taxpayer dollars and further prove the registry is a waste of time, and have lots of your own time on your hands, spend your days switching out stocks and calling the CFC back over and over again to re-classify your M1 Carbine from restricted to non-restricted.
I don't write the laws, and yes they are retarded. I am simply only pointing them out and their obvious stupidity.
And as for the comment on taking a folded stock M1 Carbine to a range and a range officer not pointing it out, I would presume a ranger officer is more interested in range safety rather than taking a tape measure out of their pocket just to see if an M1 Carbine is .5" too short to uphold the Firearms Act. But I could be wrong on that one.
FWIW, I own a non-restricted M1 Carbine because I want to be able to take it to my own private range and shoot it without concern of breaking the law. MY OWN OPINION IS buying a restricted M1 Carbine is a waste of money. If I never intended to do this, I would have spent $200.00 less and bought a restricted one.
I paid $750.00 for mine, and another $40.00 for 2 spare mags. I can hunt with it, take it to the range, take it to my own private range, and can more easily sell it then a restricted one. Seems like a good deal for me.
Do you guys know the price they go for ? Thanks guys ! 
