Have had lots of correspondence with the owners of AIA and they have them, someone in Canada just has to order them.
Only way is to go to Marstar, buy a complete AIA rifle, keep the mag and try to sell the rifle...
AFAIK AIA is defunked.
Actually, they do. You have to Drummel about a millimeter off the bottom of the lug, and they will click into the AIA. It's the only use I have now for my 5 round M14 mgs. They insert and come out easy from the AIA.
Basically, to get one, you need a time machine, and if you had a time machine, you'd be better off shooting in 1989.