Depends on what you were convicted of.
Generally speaking, no, because if you have a DV conviction, you are prohibited from owning a gun by federal law.
Under FEDERAL law, there is no time limit
I'm not sure specifically about South Carolina, but if the conviction was some sort of felony, federal law prohibits you from purchasing a firearm.
Depends on the misdemeanor. If the conviction was for a crime of domestic violence, or for unlwful use of controlled drugs, then FEDERAL law prohibits sale.
Debs's conviction reinforced federal authority to halt strikes
Expungement won't restore firearms rights. It places your conviction out of the public eye; it doesn't make it go away. If your conviction was for something which is ONLY a felony at state level (not under federal law), you can apply for relief of disability. If it's a federal felony, or a domestic violence conviction, you're pretty much out of luck.
No.
Get their conviction overturned.
IF your conviction was for a State crime, you MAY be able to petition for restoration of gun rights. This WILL require an attorney. Be sure to get this right, since the penalty for being a felon in possession is 5 years in a Federal prison. Process will vary state to state- which is why you need an attorney. If your conviction was for a Federal felony, unless you have received a Presidential pardon, there is no way to remove that bar.
It depends on where you are. In the U.S. each state sets its own rules. I can tell you, by federal law, the only misdemeanor that disqualifies you from owning a gun is a misdemeanor conviction for domestic violence.
A person is more likely to be convicted in a state court than in a federal court.
If it's a felony only at state level, it might be possible; if you were convicted for something classed as a felony under federal law, you cannot.