The article profiles ballistics analyst Richard Smith at the Los Angeles Police Department. Smith, 47, has gained a reputation as one of the most gifted practitioners of his craft anywhere in the country. With the eye of a master jeweler, he's able to recognize- and remember-the subtle nicks and scorings left on bullet casings that distinguish one firearm from another. So adept is Smith that last year the LAPD instituted a "Walk-In Wednesday" program, in which detectives from all over the department can bring him guns that have been used in crimes to see if they match weapons employed in other cases. From 1998 to 2002 Smith recorded more than 400 "cold hits," meaning he was able to link weapons from separate incidents and thus increase the chance of police making an arrest. As Smith is the first to acknowledge, though, his work isn't all that glamorous. For one thing, in contrast to the spiffy world of forensics depicted on the various CSIs, he toils in a cavelike warren of offices in a nondescript building in northeast L.A. Smith sometimes spends as much as eight hours working with a single shell casing. Smith got into forensics more or less by chance. Born in North Carolina, he was raised all over the South, where his father was a Baptist minister who worked closely with the Reverend Dr. Martin Luther King Jr. in the civil rights movement. After graduating from college with a psychology degree, he focused on becoming a police officer in California, where his parents had moved. Joining the LAPD in 1981, he started his career in uniform, then went undercover in some of the city's most blighted neighborhoods, including South Central. Tough as it was, he loved the work, which also enabled him to showcase his remarkably acute eye. INSET: A COLD HIT.