A teenager takes aim with a Colt at the National Rifle Association's annual meeting in Houston on Saturday.
Porter (64), the son of another Alabama lawyer who served as NRA president from 1959 to 1961, is likely to succeed David Keene on Monday in the two-year post at the nation's leading gun-rights organisation.
The longtime member is chairperson of the legal affairs committee for the NRA, which has headed off federal attempts to approve new gun ownership restrictions, including a US Senate proposal last month for expanded background checks.
Porter told NRA members at their annual convention in Houston on Saturday that President Barack Obama was "AWOL" on border security, the deficit and national security, but "scheming and plotting" to take away Americans' gun rights.
"There is nothing, nothing that criminals do with guns that isn't already against the law," Porter said.
In a speech to the New York State Rifle & Pistol Association in June 2012, Porter called Obama a "fake" president and US Attorney General Eric Holder "rabidly un-American".
The NRA's focus is far different now from what it was when Porter's father, Irvine Porter, led the organisation. The NRA then focused mainly on shooting and hunting. Its emphasis shifted in later decades to lobbying against restrictions on guns.
Porter, the NRA's first-vice president, who by tradition is expected to be elected president on Monday by the board, introduced the outgoing president, Keene.
"If I have anything to say about it, you just heard from your next president of your National Rifle Association," Keene told the crowd.
Wayne LaPierre, the NRA's executive vice-president and chief executive, remains the most visible leader of the group.
Challenging restrictions
Keene told the Washington Times earlier this week that Porter would be a "perfect match" as NRA president as it focuses on court challenges to state laws restricting gun ownership.
"As we are likely to win most of the legislative battles in Congress, we will have to move to courts to undo the restrictions placed on gun owners' rights in New York, Connecticut, Maryland and Colorado," Keene told the newspaper.
Connecticut and New York expanded assault weapons bans and restricted the capacity of ammunition magazines after a gunman killed 20 students and six adults at a Connecticut school in December.
Colorado, where a gunman killed 12 people and wounded 58 others in July 2012 at a midnight showing of the Batman movie The Dark Knight Rises, approved restrictions on the size of ammunition clips and universal background checks.
Porter, a 1971 graduate of the University of Alabama, told the New York group last year that the fight to protect the Second Amendment to the US Constitution setting out the right to bear arms had just begun, and that Obama's "entire administration is anti-gun, anti-freedom, anti-Second Amendment".
On Saturday, Tom King, an NRA board member from East Greenbush, New York, said Porter was a likable family man and successful attorney who would be a good NRA president.
"I say things that are controversial too, everybody does," King said. "If you want to take something out of context and say, 'He said that, that's controversial,' and you want to attack him for that, that's your prerogative or anyone else's prerogative, but Jim is a good man. – Reuters