It is a factor of the war and of the fact that many former combloc countries and others are switching from X39 to 5.56.
It is a simple issue of supply and demand. Normally the US and NATO countries "set" the price of 5.56 at the high end. Other countries fall in line under them. However due to demand the NATO countries cannot supply, so the other players raise their price to meet the NATO price.
World price for new Grade 1 M855 ball is USD$0.27-0.32 per round, no matter who you buy from. 223/M193 is a bit cheaper. You do the math on shipping, permits etc to arrive at the CDN retail price.