Two old gunfighters, Beretta and Smith & Wesson, will be shooting it out next month over a lucrative Pentagon contract -- but some say the duel shouldn't be taking place at all.

The shoot-out, a series of performance tests at the Aberdeen Proving Ground in Maryland, will decide which company will supply the military with 142,000 9mm semiautomatic pistols.

Beretta USA, the Accokeek, Md.-based American subsidiary of the Italian arms maker Fabrica d'Armi Pietro Beretta, has beaten Smith & Wesson and six other weapons makers once before, winning a landmark 1985 contract worth $75 million to supply the Pentagon with more than 320,000 of its M9 9mm pistols, replacing the venerable Colt .45. The new competition is for a contract for additional guns.

Although confident the Army will award them the follow-up contract, Beretta executives are not putting all their bullets in one basket. The powerful M9, with its 16-round capacity, has become the weapon of choice for police around the nation in the fight against heavily armed drug dealers, and more than 200 police forces across the country now carry the gun, including the Maryland State Police, the Prince George's County police and the Anne Arundel County police.

But police departments generally buy just a few hundred pistols, so the big prize for 9mm weapons makers clearly is the upcoming contract to supply the military with $30 million worth of weapons.

Beretta, its congressional supporters and several military procurement officials are upset that Beretta must compete for the contract after winning the bidding for the first round of handgun purchases.

The upcoming performance tests would not be taking place at all, many observers say, if Springfield, Mass.-based Smith & Wesson had not called the tests for the initial contract unfair, and persuaded two influential Massachusetts congressmen to attach an amendment to a 1986 spending bill that forced the Army, over Pentagon objections, to conduct a new round of testing for a pistol to supplement the initial Beretta order.

The Army, which serves as the pistol procurer for all five services, said that buying a non-Beretta handgun would defeat the purpose of purchasing the Beretta in the first place -- to equip the entire armed forces with the same sidearm.

A non-Beretta purchase would "radically complicate the logistical system we have in place," said Col. Richard Williams, chief of the Army's 9mm pistol program. "This is very politically sensitive. Our intent was to standardize on one weapon, but because of everything that has gone on, they felt that theirs was the right approach. We don't necessarily agree with that."

Tom Keaney, a legislative assistant to Rep. Edward P. Boland (D-Mass.), one of Smith & Wesson's key congressional supporters, said the Massachusetts company felt "the original contest was unfair."

Smith & Wesson argued that its gun was eliminated because one of the three samples entered in the endurance phase of the tests broke before firing 5,000 rounds, the minimum necessary to qualify. But the two samples passed the test, and the Massachusetts arms maker maintained that the weapon should have qualified for the next round of testing.

The Army disagreed -- Williams said the Smith & Wesson entry failed minimum standards and did not make the finals. "They were never in the running," he said. But the General Accounting Office sided with Smith & Wesson.

Smith & Wesson Vice President Robert Hass said his company has improved its 9mm entry. "The Army will see the changes when we submit, and we think they'll be favorably impressed," he said.

Despite the controversy, Beretta, with the help of Reps. Steny Hoyer (D-Md.) and Tom McMillen (D-Md.), who both represent parts of Prince George's County, preserved the $75 million contract for the first 320,000 guns, and more than 110,000 Beretta pistols have been delivered to the military so far.

But all has not gone smoothly with that contract. The Army temporarily halted delivery of the Beretta pistols last November after the handles of several weapons cracked. And earlier this year, a key component of the gun -- the slide mechanism -- malfunctioned on two weapons. Beretta said the cracking problem was not important, and said the slides were malfunctioning because of inappropriate ammunition, and the Army, apparently satisfied with Beretta's handling of the situation, resumed accepting deliveries in May.

Despite the recent problems, Beretta officials say they are ready for the competition against Smith & Wesson, along with any other pistol manufacturer who sends 30 samples to the Army by Aug. 17.

Beretta has not only been trying to protect its name with the Pentagon. Last week, Beretta also filed suit in New York against General Motors, charging the giant automaker with stealing its name.

The lawsuit, which asks for $250 million in damages, claims GM infringed on its trademark by naming its best-selling new sports coupe Beretta.

GM claims that the employee who chose the name did not even know that Beretta is an arms manufacturing company.

If Beretta loses the $30 million Pentagon contract to Smith & Wesson or another competitor, company executives said they will not be mortally wounded.

One reason: the snowballing popularity of the M9, known commercially as the 92F in law enforcement circles.

Beretta, which does not release revenue or profit figures, now has about 440 employees making guns at its Accokeek plant, triple the number when the company set up its U.S. operation in 1977.

Beretta executives said the company's growth should continue even if it loses the Army contract.

"Obviously, we would welcome an additional contract with the Army," said Jeff Reh, Beretta's contract manager, "but the demand for the Beretta 9mm pistol is so great right now that even in the absence of such a contract, we don't see a diminution of either employment or sales, potentially for decades to come.

"Beretta is now clearly established as the weapon of preference for law enforcement agencies."

One police officer who says he is pleased with Beretta's product is Gary Hutchison, the chief firearms instructor for the Prince George's County police.

He said 55 street officers began carrying the Beretta last week, five months after County Executive Parris Glendening announced that the county police would switch from a six-shot Smith & Wesson .38 revolver to the semiautomatic Beretta, which has a 16-bullet capacity.

Hutchison said recently that one of the Beretta's primary advantages over a revolver is psychological.

"In case you need more than six rounds, you're in trouble anyway," Hutchison said. "Most shooting situations take three, four, five shots. With a six-shot, when you hit four, you panic, you think, 'Now what I am going to do?' With a six-shot revolver, you would almost not take a shot for fear that you would miss. With the Beretta, you have the extra bullets, so there is no panic."

Hutchison said he feels the semiautomatic Beretta is a better weapon than a revolver for other reasons.

"It is much faster to reload," he said. "For the average person to reload a revolver, he needs five seconds. With the Beretta, it takes two seconds to change magazines."

Hutchison said he prefers the Beretta 92F over Smith & Wesson's 9mm pistol because the Beretta's shell-casing discharge system is more reliable.

"They've gotten the technology in their 9mm to the point where it's pretty dependable," Hutchison said.

Reh said that feedback from police departments now using the Beretta has been positive.

"We haven't received negative comments at all from police," Reh said. "They love the pistol."