How can the National Rifle Association help convicted felons obtain a firearm?

They can't. And won't. Convicted felons are prohibited from owning (or even "obtaining") a firearm in all 50 states. But if civil rights have been restored (usually by the state governor or a clemecy board), then the person can possibly obtain a firearm legally. But he/she would not need the help of the NRA to do so. One more point about the NRA: convicted felons cannot be members of the NRA.