Keane, senior vice president and general counsel at the National Shooting Sports Foundation.

"What we've seen over the last several years are many first-time buyers," he said.

Several firearm and ammunition manufacturers are in the process of adding capacity, Keane said, such as North Haven, Conn.-based gun maker O.F. Mossberg & Sons boosting factory production at its Texas facility.

The numbers

Point-of-sale federal background checks required for retail firearms transactions — the National Instant Criminal Background Check System — saw a record 21 million background checks in 2013, compared to 19.5 million checks in 2012 and 16.4 million in 2011.

While background checks, which have been compiled online since 1998, don't automatically mean a gun was sold at the time of the check, they're the industry proxy for measuring sales trends.

There were 2.7million checks nationally in December 2012 and 2.4 million in January, the most active months in the system's history, according to federal data.

There were 503,979 firearms background checks in Michigan last year, FBI records show, topping the 430,405 checks in 2012 and the 356,635 in 2011.

Michigan saw 59,445 checks in December 2012 and 60,852 checks in January 2013, the two largest months in the system's history for the state. Michigan background checks fell off to 29,521 in July before creeping back up to 40,320 in October, another 39,996 in November and 37,647 in December — traditionally higher months, gun dealers say, because of hunting season and holiday shopping.

The public thirst for firearms also fueled an uptick in arms dealers in Michigan.

There were 4,318 active federal firearms licenses, needed