My understanding of the law is that it is legal to buy an antique without a PAL(R) because ammunition is ostensibly unavailable for it. Some guys make some, some antique ammo survives, at inflated prices.
However, there is nothing in the law that permits you to carry an antique handgun, with ammo or not. If you are caught with one out in public you will be treated the same as if carrying a regular handgun.
http://www.rcmp-grc.gc.ca/cfp-pcaf/fs-fd/antique-historique-eng.htm
