How will that effect us in Canada? Well if history is an indicator every 5.56mm owner in the US is either purchasing thousands of rounds as we speak or planning to in the very near future. This means it will become very difficult for sporting stores in Canada to get new orders of 5.56mm ammunition.
UPDATE:
According to TheBlaze.com the ATF is now backing away from the re-classification of M855 rounds. The ATF calling it a "Publishing Mistake" OR does sanity prevail?