South Dakota defines legal firearms in terms of muzzle energy, not caliber. See the link below.
Depends on what you are hunting. See the link below to the Illinois Game Regulations.
Over 3000 yds
A "sniper rifle" is simply a rifle employed for that purpose. So long as the "sniper rifle" meets the criteria and restrictions for hunting firearms in the state you're hunting in, you can use it.
Depends on the laws where you live.
caliber limitations are set by the hunting ministry in your region, eg 243 for deer(smallest) 22lr for smll game eg rabbits and so on
Yes- see link at bottom of page.
rifles are used for war and legal hunting. I want to use it for shooting "cans".
You will have to define "sniper rifle". There is no meaning to that term, other than an accurate scope mounted rifle. That includes most hunting rifles.
.22-250 Remington is a caliber and not a type of rifle. Several manufacturers have made rifles in this caliber. Without knowing the exact make, model, and condition of the rifle this question cannot be answered.
If you can legally own a suppressor, you can just as legally mount it on a hunting/sporting rifle - however, you can't do this when you're actually hunting with those firearms.
18 for a shotgun/hunting rifle, and 21 for a handgun.
No you need pretty serious permits just for a hunting rifle. No automatic fire arm is legal in Canada