Usually one finds a supply of ammo before buying a gun chambered in a not-so-available cartridge.
If I do recall, Hornady has factory loads available in 120 and 140gr AMAX.
EDIT -
Also available from Hornady is a 120gr GMX and a 129gr SST if you are going to be hunting.
This is all that I know of for factory loads.
Contact your local shops. Most likely will have to place a special order for this stuff. A quick search turned up these places that are Hornady dealers:
Pro-Line Shooter II Inc.
1426-9th Ave SE
Calgary, Alberta T2G0T5
403-265-6666
Russel Sporting Goods
128-8228 Macleod Trail South
Calgary, Alberta T2H 2B8
Wholesale Sports Calgary
225-58th Ave SE
Calgary, Alberta T2H 0N8
