It can be shipped through canadapost as well, although not a single representative at the post office will admit to it, and they won't know the regs.
Canadapost does in fact, publish a pamphlet indicating that ammunition is classed as a dangerous good and cannot be shipped since it is contrary to certain sections of the dangerous goods act (i think the act is called that, I can't quite remember).
But, there are provisions in this act allowing for the shipment of small quantities of hunting/sporting ammunition, all packages should be marked "limited quantity, consumer commodity" or LQ CC.
Anyways, I am a little fuzy on the details, so make sure to do your own research, but I remember looking into this a little while ago and concluding it was ok.
Cheers