It depends on what you wanna hunt mate. I've got a .223, .243, .300, and .375H&H, as well as a .22 and shotty. A .223 is the best calibre in my opinion if you arent looking for buffalo or bulls. If legal, I'd feel very comfortable shooting anything else in Australia with my .223. Good luck, let me know what you decide.
Game of all size and shape is hunted, and the calibre varies in accordance with what it is you're hunting. If you're hunting elk, you're not going to use the same calibre you would hunt squirrel with, and vice versa. A hunting rifle is simply a rifle which is used for hunting - that in itself doesn't determine what's being hunted, and it would be impossible to determine an average calibre, given that not every hunting rifle was a purpose built rifle - some hunters, for example, used decommissioned military rifles such as the SKS.
Smaller than 20mm.
for a rifle it is thought to be a .50 calibre but a gun company made there own for there own sniper rifle the .408 calibre
You will usually find this range of scope on a centre fire rifle. As to what specific calibre of rifle, you can't pin point it. This is a pretty all-around scope that is good for varmit hunting, deer hunting and even big game hunting.
The .243. It's basically a necked down .308 Winchester.
This all depends on the calibre of said rifle make and model :)
The Mark one and two Enfield Bolt Action Rifle in calibre .303 were the standard issue rifles (Australia) in World War I.
The Winchester Company introduced the 32 Calibre rifle in 1873. For it they created four different types of bullets including the Winchester 32 special.
It's Japanese, and the rifle uses the 7.7x58mm Arisaka cartridge.
For a rifle it would be the 2 Bore.
No
It's a rifle, in fact very small calibre. .22 is roughly 5mm's.