hi john
chris has given some very sound advice. i would like to add to what chris has said, but i only do so as a heads up. personally, i feel that the current laws involving guns, gun parts, and military ordnance such as motars, grenade launchers, bazooka's, and other stuff important to collectors and re enactors is total fubar.
as it stands, replica's are prohibited as is their manufacture, but the real deal, which has been de activated is o.k. also, and with the exception of .22rf, semi auto magazines must be blocked to five rounds in capacity. i can only assume this extends to full auto as well. as much as it makes me cringe to say the above, i say it with "cover your ass" in mind because on paper, the law obiding citizen's and collectors are the criminals, while for the real thugs, it's life as usual. although i don't have the act in front of me, i think that items of larger bore, such as a 2" mortar, would be subject to the controlled goods act, which as of lately, has been causing some problems for some people. if you join the forum that chris suggested, go to the search function and type in "milkor", and be prepared for lots of reading. hopefully with a majority in ottawa, some of this crap will be relaxed and funds will be funneled into getting the real criminals for a change.
mike