David Boreanaz

NEWHALL, Calif. -As non-stop gunfire pounds eardrums at the Oak Tree Gun Club, a firing range 40 minutes north of Los Angeles, a handsome father lifts his unflinching 31/2-year-old son up onto his shoulders. "This is a hobby," he tells the boy as he points to the shooters. "These gentleman are safe and responsible adults." Bones technical adviser Mike Grasso guides David Boreanaz, who plays a former sniper. Bones technical adviser Mike Grasso guides David Boreanaz, who plays a former sniper.

Dad is 36-year-old TV heartthrob David Boreanaz, who played Sarah Michelle Gellar’s bloodsucking lover boy, Angel, for seven years on Buffy the Vampire Slayer and its Angel spinoff. Boreanaz now helps identify bodies and catch killers as FBI special agent Seeley Booth on Fox’s Bones (tonight, 8 ET/PT).

Like Angel, who once terrorized Europe as a murderous vampire, Booth, a former government sniper, is atoning for past sins. His intention: to catch as many murderers as the number of lives he took.

As Boreanaz’s son, Jaden, climbs rocks under the supervision of Boreanaz’s nanny, assistant and publicist, the actor takes position behind a barricade and aims a .40-caliber Glock 35 handgun at a target. To authenticate his role, Boreanaz trains with real-life homicide detective Mike Grasso of Nine-One-One film technical advisers.

Grasso, who also has helped Arnold Schwarzenegger, Sylvester Stallone and Nicolas Cage fire guns, says, "Schwarzenegger can really shoot, but David has picked it up faster than everybody else."

As Grasso positions Boreanaz’s body, he tells him, "Bring your elbow into your body and straighten out your left leg. ... You want a minimum amount of your body exposed to the target."

"The whole trick," Grasso explains, "is for David to look like he’s got 15 years’ experience doing this. The gun should just be second nature."

Tonight’s episode of Bones will introduce Booth’s 4-year-old son, Parker. To up the stakes during training, Grasso advised Boreanaz to envision a scenario in which his own son was in jeopardy. Primed with that discomforting incentive, Boreanaz hit his target dummy between the eyebrows for the first time. "Mike made it personal for me," Boreanaz says. "I was shaking the gun a lot more, but it worked."

Boreanaz is trying to ensure that Jaden adopts the same values he learned growing up in Philadelphia with his TV weatherman dad, Dave, and mom, Patti. "I want to teach him, like my father taught me, to respect people and be responsible. Bringing him here today is not about going to a shooting range; it’s about being with his dad."

On several occasions, Boreanaz has had to stand up in public to protect the honor of Jaden’s mom: Boreanaz’s wife of four years, Jaime Bergman, 30, a former Playboy Playmate and St. Pauli Beer girl who now works as a Prudential real estate agent and comedian. They met five years ago at a Valentine’s Day party. If anyone disrespects her, Boreanaz says, he "deals with it as any Italian would. I fight with fists, not guns. I’m a lover, not a fighter."

But Boreanaz has not ruled out the possibility of purchasing a gun for personal protection. "Doing this role is research in getting an understanding of how comfortable I am with a gun in my hand. You want to protect your family from anything that comes into your home so that your child is there the next day and not an intruder."