Last weekend, an auction held at his Florida home saw the item, described as “a one of a kind Trump Glock from the 45th President of the United States Donald J. Trump,” go up for bidding during a charity event. Pictures circulating on social media show the gun being presented at the auction, with news website Meidas Touch saying that bidding for the item began at $10,000.
However, the transaction could land the former U.S. president in considerable trouble, given that federal law prohibits those under indictment from transacting firearms. Trump is embroiled in active legal proceedings, having testified at a civil trial over the New York investigation into financial fraud at the Trump Organization. The former president has denied all wrongdoing and repeatedly said that the ongoing federal and civil cases against him are part of a political witch hunt.
Looks like up to 10 years, but this is from 2013 so it could be different now:
https://www.justice.gov/sites/default/files/usao-ut/legacy/2013/06/03/guncard.pdf
At the top, 922 (n).