Legal implies a law. Laws are based on where you are. We get questions from many different nations here. In the US, there is no limit on the size or caliber- except that firearms larger than .50 caliber without a recognized sporting use (such as a shotgun, elephant gun, etc) must be registered as a Destructive Device, and a $200 Federal tax paid on the transfer of it to you. But if you want to own your very own cannon you can (and some folks do)
.500s&w
Not legally. It's illegal for a felon to own a gun in any state.
The BATFE web site has information that can assist you in answering your question.
Not legally
If you mean "own" a gun, no. Felons cannot own or possess guns.
There is no registration of ordinary Title I firearms in Georgia. You may pawn a gun that you legally own. You may not pawn a gun that you do not legally own.
There is no registration of ordinary Title I firearms in North Carolina. You may pawn a gun that you legally own. You may not pawn a gun that you do not legally own.
Not legally.
Yes, it is.
Nothing. There is no gun registration in Virginia.
They can't legally own, possess, or have access to firearms, period.
Yes. Firearms of that caliber can legally be owned in Canada.