Gun sales soared last month: 2,767,699 federal background checks for firearms purchases were run, the highest March number since the FBI began releasing data in 1998.

While there is no exact data on firearms purchases in the U.S., the FBI's National Instant Criminal Background Check System is used as a barometer for gun sales. Adjusted for permit checks, such as concealed-carry applications, March checks were up 10.8 percent from the previous year, totaling 1,503,967. Handgun checks increased 3.9 percent, while long-gun checks increased 17.3 percent.

The strong background check data sent shares of publicly traded firearms companies climbing. The industry has faced dwindling stock prices since the 2016 election, as slowed sales affected American Outdoor Brands, formerly known as Smith & Wesson, Sturm Ruger and Vista Outdoor. Under a Republican president and Congress, the risk of gun-control legislation was minimal, and fear-based buying stalled.

Following the mass shooting at a Parkland, Fla., high school in February, a nationwide gun control debate has been underway. Congress advanced some firearms regulation measures last month and the White House backed a bump stock ban.

Rommel Dionisio, a managing director of equity research at Aegis Capital who focuses on publicly traded firearms companies, said March's background check numbers confirm the gun industry is showing signs of a rebound.

"The March data confirmed the re-emergence of fear-based buying," KeyBank Capital Markets analyst Brett Andress wrote in a note sent Tuesday morning, "the primary tell being the more politically sensitive long guns rising 17.3 percent."

In February, long-gun checks were up 3 percent nationwide.

James Hardiman, an analyst at Wedbush Securities Inc., a securities firm and investment bank, also noticed the long-gun uptick. The rise, he wrote in a note, confirms that "the increased buying activity is largely due to the heightened talk of gun regulation following February's tragic shooting in Florida."