I have never dealt with
Cheap Gun Parts and I don't know of anyone that has, they do state that
"All Foreign orders where the parts total is over $100 requires an import permit. (Note: Canada has a $500 parts limit)
Customers are responsible for all custom fees.
ANY ORDER VALUED AT OVER $100 (OR $500 FOR CANADA) WILL NOT BE EXPORTED TO A FOREIGN COUNTRY.
We will not be responsible for items shipped internationally and either lost in shipment or seized by customs."
Until there is a proven track record I'd be a bit leery but you pay your money and take your chances.
Kidd parts can be had through Jo-Brook Enterprises, though they don't have stock at present.
Milarm in Edmonton has some Volquartsen parts and
IF you time it right when they get an order in they have a supply. Miss it and you can wait 6 months. Prices I've seen there are high. You have to phone and talk to John, do not try email or trust the web site.
Canada is not a great place to get US parts.