Washington ? As the clock counts down on the decade-old ban on selling and buying assault weapons, phones have begun ringing off the hook at ArmaLite. Customers want to know when the newly outfitted AR-15 rifle will be ready.

“People are excited. They’ve been waiting for this for a long time, and we’ve been preparing,” said Jodi DePorter, a spokeswoman for the Geneseo, Ill.-based gun maker.

Unless Republican congressional leaders have a sudden change of heart, the assault weapons ban — a centerpiece of the 1994 Crime Bill — will expire at midnight on Monday.

The federal law applied to 19 semiautomatic weapons, which fire one round and automatically load each time the trigger is pulled. Automatic weapons, which remain illegal, are designed for military use and shoot without stopping.

ArmaLite plans to ship newly outfitted assault rifles just hours later to customers who were so eager to get the .308 and .223 caliber semiautomatic rifles that they’ve pre-ordered them.

Gun manufacturers are gearing up for a wave of business once the ban sunsets. They’re offering promotional coupons online for extras such as free flash suppressers and boxes of high-capacity 15-round magazines.

Joseph Vince, the former chief of the Bureau of Alcohol, Tobacco and Firearms Crime Gun Analysis Branch, predicted that the end of the ban “will cause a frenzied buying spurt.”

Law enforcement — which credits the ban with helping drive down the crime rate to record-low levels in the last decade — says they’ll once again be outgunned by criminals.

Several dozen police chiefs from around the country converged on Washington recently to lobby members of Congress to reauthorize the ban.

To purchase an assault weapon, customers must undergo a criminal background check. If they pass, they can walk out with a gun. Seven states — California, Connecticut, Hawaii, Maryland, Massachusetts, New Jersey and New York — have their own assault-weapon bans that will remain in place.