ON a summer day in 1993, Gian Luigi Ferri walked into a Nevada pawn shop and bought two TEC-DC9 semiautomatic pistols. A few days later, he used them to kill eight people at a San Francisco law firm.
Convinced that this rapid-fire weapon serves no purpose other than mass slaughter, the families of Mr. Ferri's victims are taking aim at the manufacturer. Last week, a California judge found sufficient grounds for the families to sue Intratec, the Miami company that produced the TEC-DC9 before Congress banned it in last year's crime bill.
The case will be the first product-liability suit against an assault-weapon maker. Supporters say that if a company makes lethal products, it should pay for the havoc they wreak -- a claim often made against alcohol and tobacco companies.
But critics warn that forcing a manufacturer of a legally sold product to pay for its misuse could spur frivolous litigation aimed not just at gun makers, but lawn-mower companies or burger stands.
While legal experts say the Intratec suit will be difficult to win, they acknowledge that if it succeeds it could set a precedent for other states and effectively shift the battle over guns in America from state and federal legislatures to the courts.
''We're elated,'' says Mark Polston, a staff attorney at the Center to Prevent Handgun Violence, the group that filed the Intratec suit. ''The TEC-DC9 is the No. 1 assault weapon tied to crime. The primary market for it is criminals.'' Mr. Polston says the suit could introduce ''a whole new principle of accountability'' in the weapons industry.
Pointing to polls that show 70 percent of Americans support the crime bill's assault weapons ban, Polston says the suit has a chance of success because it mirrors public opinion. Critics say the case is an example of the reckless suits that make companies pay for the actions of lunatics.
''The nub of the problem with this suit is that it is based on perceptions,'' says John Snyder, spokesman for the Citizens Committee for the Right to Keep and Bear Arms in Washington. ''The basis for deciding what is dangerous ... is arbitrary.'' The vast majority of TEC-DC9s, he notes, are not used to commit crimes.
According to Teresa Moran Schwartz, a law professor at George Washington University in Washington, the Intratec suit is unlike most product-liability cases. Although Ferri's TEC-DC9s were legally manufactured in Florida, and legally sold in Nevada, the judge ruled that Intratec should have foreseen that the gun could be used to commit crimes in California, where such weapons have been banned since 1989.
Instead of targeting a faulty product, the case seeks to prove that assault weapons, even when they work correctly, are ''abnormally'' dangerous -- and that the manufacturers are negligent in producing them.
Only once has this argument been successful. In 1985, the Maryland Court of Appeals ruled that selling the pocket-sized guns known as ''Saturday night specials'' was ''an abnormally dangerous activity'' because the guns were so easily concealed. But the ruling was preempted when the state legislature outlawed them.
For years, people who claim smoking-related ailments have used the same legal argument in suing tobacco companies -- so far, to no avail. In tobacco cases, Professor Schwartz says, plaintiffs have to prove that cigarettes have no social or recreational utility -- an idea that no jury has accepted. Also, juries usually consider the smokers who bring claims responsible for their own health problems.
But Schwartz says that assault weapons may be the product most likely to be the subject of a successful liability suit. It's hard for people to see any legitimate purpose for assault weapons other than a criminal one. Unlike smokers, victims of assault weapons are undeniably innocent.
Dick Danard, a professor at Northeastern University School of Law in Boston, says that the stakes are high in the Intratec suit. If the courts don't act, he says, legislatures surely won't, because, unlike judges, ''If these questions come before legislators, the lobbyists can get to them.''
Yet gun-rights advocates and civil libertarians say the ruling is being overplayed. Richard Feldman, a spokesman for Intratec, argues the suit will not succeed because courts almost always reject the idea that criminals or chronic smokers are not responsible for their actions because something was sold to them.