The special-effects gurus who host the television show "MythBusters" were cast Wednesday in an ignominious role: visiting a home on a quiet street in Dublin and apologizing to a family for firing a 30-pound cannonball through their front door a day earlier.

"Come in," said Hitha Shetty, 39, ushering show hosts Jamie Hyneman and Adam Savage across a floor still speckled with paint and plaster.

Behind Shetty was damage more likely to be found on a pirate ship than a two-story tract home. A round hole scarred an interior wall and, beyond that, another hole showed where the cannonball had exited the upstairs master bedroom as Shetty's wife, Seema, napped with the couple's 2-year-old son.

After assuring Shetty, his two children, his wife and her parents that they would never again blast a home with heavy ordnance, Hyneman and Savage said the incident was the worst thing that had happened during thousands of experiments over eight years on the Discovery Channel show.

They also promised they wouldn't air the footage they had filmed of the near-catastrophic cannon shot.

"It's a wake-up call," said Savage, 44, who like his 56-year-old partner lives in San Francisco. "Honestly, the feeling of embarrassment is not something we're indulging in right now. We feel for the families and the people affected by this."

He added, "Some people watch our show and think that we're reckless. Others watch our show and they see we take safety seriously. The fact is, the latter is the case."

Savage and Hyneman were not present at the Alameda County bomb ordnance range - which the show has used for years and is nearly 1,000 yards west of the Shetty home - when the cannon fired at 4:15 p.m. Tuesday.

They said the three other stars of the show - Tory Belleci, Kari Byron and Grant Imahara - had been "calibrating" a homemade cannon, firing a ball made of either steel or cast iron into water barrels and a brick wall to make sure it had the same power as a historical cannon.

Stone cannonballs

The ultimate goal, they said, was to go to a more remote location and use the cannon to fire stone cannonballs into a replica castle wall.

"The myth was whether or not a stone cannonball could actually breach a castle's walls," Savage said.

However, Hyneman said, the crew suffered "muzzle lift," and the cannonball arced across Dublin. It bounced on the Shettys' driveway on Cassata Place before racing through their home and flying across six-lane Tassajara Road.

It then bounced off the roof of a second home before smashing into another resident's Toyota Sienna minivan, coming to rest on the floorboards.

"When you start to look into the data of what cannons can actually do, it's actually quite shocking," Savage said. "They're very efficient projectile-hurling weapons. It's a lot of power, and the power got away from us."

The shot took the Alameda County Sheriff's Department by surprise as well. The agency, which runs the ordnance range, halted all non-emergency operations there pending a review of safety policies, said department spokesman Sgt. J.D. Nelson.

Before receiving his visitors, Hitha Shetty said the novelty of the situation didn't soothe his anger. He said residents should have known a dangerous experiment was being staged. He also hinted at firing back with a lawsuit.

"The kids are usually playing there," he said of the path of the cannonball. "I want to make sure this doesn't happen again. And, of course, they need to pay for this. Not just the physical damage, but everything else."

Talk of the town

As he spoke, his street filled with neighbors who wanted to see the dent in the pavement where the ball bounced and the hole in the front door. Some kids snapped photos and pocketed shards of concrete as souvenirs.

"You get to see this probably only once in your lifetime," said Sameer Paila, 9, after he took video with his dad's iPhone.

The show hosts signed autographs in the street but resisted humor. After Savage posed for a picture with two neighborhood girls, he said, "You'll forgive us for not smiling. It's not smiling time."