A reality television stunt that went awry sent a cannonball careening into a residential Dublin neighborhood late Tuesday afternoon, punching holes through the front door and a wall of a home and smashing a minivan's window, but luckily leaving area residents unharmed.

The cannonball was fired as part of an experiement for the Discovery Channel show MythBusters.

The Alameda County Sheriff's Department confirmed that at around 4 p.m. a cannonball was "misfired" from the Alameda County bomb range at Camp Parks and struck a home blocks away on Cassata Place.

"This cannonball was supposed to pass through several barrels of water and a cinder block wall to slow its inertia," said J.D. Nelson of Alameda County Sheriff's Department. "When the shot was fired, it misfired. The cannon lifted."

The cannonball apparently hit something that caused it to shoot over the hillside that protects the neighborhood below.

The projectile bounced in front of the house on Cassata Place, through the front door and up through the second floor before it finally exited through the back wall.

Then it flew over Tassajara Road and ricocheted off the roof of another house before smashing through the window of a minivan where it came to rest.

"I kind of looked inside and seen a big old cannonball. And I had just got out of the van five minutes earlier," said Jasbar Gill, the owner of damaged van. "I'm glad my kids weren't inside the van. So lucky."

The sheriff's office spoke with the Discovery Channel which airs MythBusters.

"They're very sorry that this happened. And they have safety measures that are in place," said Nelson, who works as a consultant for the show, managing the tests run at the county bomb range. "They did have a misfire. And they have insurance for these kinds of things."

Remarkably, no one was hurt in the incident.

In fact, the family whose home sustained the most damage was asleep at the time and didn't realize anything had happened until the dust started to settle.

Nelson said the TV crew responded by sending a senior producer to the home and to the home of the car owner. The producer arranged to meet with their insurance carriers, Nelson said.

Nelson said the television show has used the county's bomb range more than 50 times for experiments and filming.

"We never even had any kind of an incident let alone anything this terrible," Nelson said.

Pratima Dsouza, who lives next door to the house that was hit, said she heard a loud noise and later saw police responding to her neighbor's home but thought there had been some sort of accident inside the house.   

It wasn't until she saw it on the news that she learned what had  happened.   

"Nobody came to our door and told us there was a cannonball that went through our neighbor's house," Dsouza said.

She said the bomb range where the cannonball came from is some distance from her neighborhood.   

"We can hear the sounds but we've never had an experience like that before," she said.

She said a family lives in the home that was struck.   

Another resident, Mark Hawthorne, said the cannonball bounced off of Cassata Place, leaving a dent in the concrete before crashing into his neighbor's house.   

He said neighborhood kids -- including his own -- often play outside in the cul-de-sac around where the cannonball landed.   

"It's a little scary," said Hawthorne, who has watched MythBusters on occasion. "It's easy to laugh at after it's done and no one's hurt."