Alot of these laws where people are in prison for over a year are victimless crimes, thereby these laws are forfeited to the discussion. For example selling drugs. These people in no way broke any Constitutional laws, as long as two consenting adults agree to the transaction there is nothing wrong here, unless counterfeit drugs or counterfeit money was part of the transaction.The law states if you have been convicted of an offence where the sentence is over a year in prison, then your right to owning firearms is lost. The constitution doesn't set those boundaries, the law does. So now we're not just talking murderers, but also other felonies and state offences that fit the bracket.
But yes there are laws but many of the laws are illegal and should be abolished, you cant gave un-Constutitional laws which this is what the Founding Fathers predicted would happen and when government goes to far thats why we have the 2A.