While anti-firearms activists continue to press for a ban on the sale of guns, firearms manufacturers are investigating several new technologies to make them "child proof."

• One very old technology dates back to the days of the American frontier -- when Colt Manufacturing Co. developed a Colt .32 with a trigger so hard to shoot that it was nicknamed "the lemon squeezer."

• Combination or key locks available today can be defeated by children over the age of six, say police, and gunmakers doubt their effectiveness.

• Also, trigger-locked guns may not be workable in an emergency, say skeptics; for instance, in a demonstration for reporters it took Maryland Gov. Parris Glendening (D) more than two minutes to remove a combination lock magazine from a handgun to replace it with an ammunition magazine.

Many gun owners like to keep their weapons loaded -- and most locks are designed so they can't be used on a loaded gun. That's because the locks immobilize the trigger. So removing the trigger lock could jostle the trigger and cause a loaded gun to fire accidentally.

A few manufacturers are concentrating on so-called "smart guns," which allow only an authorized user to discharge it; but the guns will be expensive -- a smart shotgun from the Mossberg Group will cost $1,000 compared to $300 for the conventional model.

Source: Martin Kasindorf and Gary Fields, "Gunmakers Fight Back: Reluctant Industry Pursues 'Smart' Guns," USA Today, April 27, 2000.