Don't know for sure, but in Ontario, I think it has to be centre-fire for all big game animals. I know a guy that uses a 25-20 for moose. I wouldn't, but he does. My wife shot her first moose with a 243 and that was legal . . . . . . and tasty. Not many people in our area use .223s, but some use 22-250 on deer, and one guy I know used his 22-250 to take a moose - - - - more of a deal about he was hunting deer with it and saw a legal moose. Dance with the girl ya brung.
I had an uncle that shot scads of moose and deer with an old model 94 Winchester in 30-30. It worked well.
Personally, I prefer something in the 308 to 300 magnum area, so my '06 usually gets the nod, but I wouldn't hesitate to perforate a moose with the 6.5 Swede.
