+1 with what Obtunded said. I started into the long range game about 2 years ago and have come a long way from what I "thought" I new about long range sticks and the skill required. Not to mention the bank roll required to back such a hobby. Thank god I got a raise or I wouldn't be shooting at all! The point is that when I started I was seduced by the "cool factor" of a 50 and I thought I had to have one. I had the budget to buy the rifle and a decent scope but I didn't realize at the time what it actually costs to feed the damn thing. You can buy loaded ammo but at the cost that's just mathematically rediculous. So that means reloading. As said before, are you an experienced reloader? Because it only takes one small mistake to have one helluva mishap. If you are an experienced loader, do you have the proper setup? If you don't that's another $1000 to $1200 for .50BMG kit plus Dies. End point is that I didn't jump in head first and did some research. I took the money I was going to spend and started building a decent .308 and only used half of my .50 budget. After ACTUALLY learning how to shoot properly out to the distances I was aiming at, I realized that bench and prone shooting was more my thing and that buying a 50 would've been rediculous at the time. Now I'm working on a 6mmBR project.
Then again, if you own every rifle under the sun except a 50 and your bank account can afford such a beast then all the power to ya.
I that case a few off the top of head that can be "got" in Canada are:
-Steyr HS-50(most availabe)- $4900-$5200
-Alberta Tactical Rifle in Calgary can build you one-$6500(check out their website)
-Alberta Tactical Rifle website also shows the AMSD Nemesis- Looks like an amazing rig, but starts at $12500
-Armalite AR-50- ~$2500(I think)
-LAR Grizzly- $1200-$1400 US(I've heard of a few in Canada but never actually seen one)
-Barret line(99.9% positive the semi-auto is prohibited)-$$$$$$$$$
Then there is quite a few options of .50BMG AR-type upper to be fitted to a regular AR lower reciever. Problems here are:
-As soon as you attatch it to that lower it's now restricted hence limited to ranges only. Good luck finding a range where you can really stretch her legs(they're out there, just really scarce).
-Getting a .50 upper is usually the more inexpensive route if you lived the 'ol US of A but by the time you find a way to get it here you probably be around the range of $3000-$4000 for an Upper that was $2000 US(anyone here with more knowledge feel free to correct me on that as that is an educated guess from research 2 years ago).
- I have read about possible problems with the recoil of a .50 damaging a AR lower. Undoubtedly, this probably happened when someone tried to attatch a 50 AR-type upper to the cheapest AR-lower on the market. That means finding a good AR lower, which in Canada will run $800-&1200. So now with the cost, it only seems logical to get a dedicated .50 rifle and not an upper-lower combo. HOWERVER, Alberta Tactical Rifle is, I belive, developing a lower for a .50 upper that would be non-restricted. If that goes through, maybe more distrinutors would start to bring in .50 uppers which would in turn lower the cost which would make that a feasable option. If this actually happens, that will be the day I start looking at 50's again.
Obviously there are more people on this board who are more knowledgable on the subject than myself, but this is basically the information I found when doing my research on the subject a couple years ago.
I've never done it myself, but I can say with almost certainty that this question has been asked here before and a quick search may answer a few of your questions.
I appologize in adcance if any of my info is out-of-date or just down right wrong. Like I said, someone who eats, sleeps, and breathe's .50 will probably comment bellow me and fix any errors in my statements.
Good luck and happy shooting!
Edit: While I was typing this, the guy who eats, sleeps and breathe's .50's actually posted above me haha.