David L said:
Hi, Bolts action will always be more reliable than the semi if you're not a gunsmitting pro! For the smallest caliber probably it is 243. If I have an advice for you, buy something that can be "universal" like 30-06, 270, 308 or 7mm mag and you will have something for every hunt!
David, the only thing "Universal" in southern Ont of the list you provided is a 270 Win...
FIlip, where abouts in S ont are you?
If you want something that will knock down deer moose, bear, and be legal to hunt varmints with in S Ont, my suggestion would be the 270 win, and but a half decent shotgun... There was one Remington 7400 for sale on here for a reasonable price.
But the best advise i can give you is this.
If your new to the whole scene, keep it simple. If you think your going to be hunting more in the southern WMU's, I'd suggest a good shotgun first, and maybe a 243. For the majority of your big game in southern ONt, its shotgun season, so a good switch barrel pump/semi shotgun might be a better purchase. And a lightweight semi/boltgun in a vary managable cal will help you to hone your shooting skills. If you choose to go on a moose/bear hunt, a rifle 12 guage would work great. for bear/deer, the 243 would work well too, but its not a stopper, than neither is the 270.
But for target shooting, groundhogs, or varmints in general, a 243 is great, and its light recoil will help you to develop your shooting without the recoil of a 270 all the time...
If I were in your shoes again, a good shotgun would be plan A, but a close plan B would be a 243, or 270...