Just hours before a contentious debate over guns is set to take place in the U.S. Senate, Chris Krier wrangles with a high-tech lathe, trying unsuccessfully to drill a tiny hole in just the right place in a part for an AR-15 semiautomatic rifle.

But for Krier, president of AdeQ Arms, getting the part right isn't his major frustration of the day. It's the political battle over the future of personal weapons ownership.

AdeQ is one of at least four companies, employing about 100 people in the Tampa area, that make AR-15-type rifles – the semi-automatic, civilian version of the military's fully automatic M4 and M16 carbines.

And business is good. Too good, in fact: Demand has been outstripping the supply of parts for AdeQ's most popular product, even before the Sandy Hook Elementary School massacre Dec. 14. So production of the company's AR-15 line has come to a halt.