Americans are lining up to buy guns in unprecedented numbers in the wake of the Newtown school shooting and the debate around tightening gun controls, with federal background checks on prospective buyers running at record levels.

New figures released by the FBI show that 2,495,440 gun background checks were initiated in January. That is the second highest number since records began in 1998, and is exceeded only by the entry for December 2012, which reached a peak of 2,783,765.

The Newtown shooting, in which 20 young children and six of their school carers were killed in Connecticut, took place on 14 December.

Since 1998, anyone wanting to buy a firearm from a licensed dealer such as a gun shop must undergo a federal background check to ensure that they are not a criminal, mentally ill or otherwise disqualified from ownership. The check is carried out in reference to a national database, the National Instant Criminal Background Check System, or NICS, operated by the FBI.

Richard Feldman, president of the Independent Firearm Owners Association, said the explanation for the dramatic spike in moves to buy guns was self-evident. "This one's easy. If the American population thinks that a product that they want – whether firearms or DVDs – may not be available in the near future, they will go for it."

In this case, what appears to be sparking a degree of panic buying are the proposals emanating from the White House and a bipartisan group of US senators to ban a range of military-style assault weapons including the kind of AR-15 used by the Newtown shooter at Sandy Hook elementary school. Senator Dianne Feinstein, a Democrat from California, has proposed reinstating the 1994 assault weapons ban that lapsed in 2004 with stronger wording that would take 158 specific models of semi-automatic assault rifles, shotguns and pistols off the market.

The FBI's latest list of the top 10 highest days since 1998 in terms of the number of gun background checks initiated tells a dramatic story. The record was set with 177,170 requests for NICS checks on Friday, 21 December – exactly one week after the Newtown massacre.

Of the top 10 entries, all but two have been recorded on or since the day of the Newtown shooting.

The surge in gun buying is paradoxical, as President Obama appears to be softening his stance on an assault weapons ban in the face of considerable opposition from Republicans in the Senate and, crucially, the House of Representatives, where the GOP holds the majority. In a speech on Monday in Minneapolis, Obama merely said that a revised ban "deserves a vote in Congress, because weapons of war have no place on our streets".

The White House strategy seems to be to put most political capital on achieving a background check on all gun sales, which is seen as having better prospects of achieving congressional approval. At the moment, private gun sellers working at gun shows or through the internet do not have to put their customers through the NICS database.

Advocates of greater gun controls point to that loophole as a major weakness in US defences against guns falling into the wrong hands. About 40% of all gun sales are classified as private and therefore not subjected to FBI monitoring.