A hot shell casing hits the floor, joining hundreds of others littering the concrete at Jackson Arms Indoor Shooting Range in South San Francisco.
Shrum centers herself and aims again.
After two days using her new revolver, Shrum's hands are sore from the recoil of every shot.
"I get that rush and power from a Magnum," said the 36-year-old Millbrae resident. "I've taken archery and thrown darts, but shooting is another way to hurl something through the air. But this is just like shooting a paper ball into the trash can. TwoPoints. Air ball."
She is among a growing number of women who are showing up at shooting ranges across the country. Many women who visit the Jackson Arms shooting gallery do it because they love the power of guns and want to learn how to protect themselves.
While there are no hard figures on the number of women who own guns, it's estimated that nationwide 11 million to 17 million women wield firearms, said Laura Browder, author of "Her Best Shot: Women and Guns in America." The National Rifle Association doesn't keep figures by gender.
Browder said the gun industry is just as focused on females as it has been over the last 200 years, but the marketing strategy now taps into their fears.
"The gun industry is saying, 'Look, the state is not here to protect you, the cops are not here, no one is looking out for you,'" said Browder, who is assistant professor of English at Virginia Commonwealth University. "There's a lot of single mothers, and there's a lot of suggestion there is no man in the house, and the woman has got to take care of herself."
That's a far cry from earlier ads that depict women as rifle-toting cowgirls and snarling buxom blondes cradling a machine gun. Meanwhile, women such as Annie Oakley, Bonnie Parker as in "Bonnie and Clyde" and Patty Hearst are still revered as armed female icons.
But Browder adds that women fighting in Iraq and Afghanistan are adding a more sobering image of women and guns.
"Many, many women are in combat and coming home wounded," Browder said. "Women with guns will seem less exotic than they once did."
Liza Normandy, a certified NRA firearm instructor at Jackson Arms, teaches women to properly shoot guns. Classes cost $50.
She said she would like to have more female shooters come in. To attract the group, Jackson Arms offers Ladies Night on Mondays. The cost of a lane for an hour is $7 instead of the regular $14 price.
Those who practice in the gallery are largely either police cadets or women who accompany their boyfriends or husbands.
Normandy has been shooting on and off for 16 years. She and her husband they met on Lane 7 at Jackson Arms are very passionate about the recreational sport.
"Shooting is like any hobby as bowling or golf," Normandy said. "It's a great way to release aggression."
Range Master Leo Manalo also teaches ladies' classes. One day, he taught a grandmother and her two granddaughters.
"Women get into shooting just like the guys do," he said. "Because it's like a mini-vacation. It's a lot cheaper than seeing a therapist. It's relaxing."
To own a firearm in California, you need to show proof of residency within the state, and pass a 30-question test to get a handgun-safety certificate. The waiting period is 10 days.
Kimberly Shrum bought her Magnum revolver on Sunday, after shooting for three months. Her father, an ex-Marine, taught her how to handle a .45-caliber semi-automatic pistol.
She said she's addicted to the power.
"Once you hold the gun in your hand and channel the power right where you want it, it's such a rush," said Shrum, who is an office manager for a financial services company in San Bruno. "But I will never get comfortable with a handgun."
Sabrina Watts, 24, is a cadet at the College of San Mateo's Police Academy. The Redwood City resident was practicing at Jackson Arms with a fellow cadet on Monday. Both used to be officers for the Peninsula Humane Society.
Watts calls herself a good shooter, but needs to stop anticipating the bang, which throws off her aim. She started shooting when she was 9 years old and learned that "guns are fun."
Watts, who plans to eventually become a police officer, believes a woman should arm herself.
"Regardless of how strong you are, a man can overpower you," she said. "If you need to protect your home, you have to do what you have to do."
Staff writer Christine Morente covers religion, families and general assignment. She can be reached at (650) 348-4333 or at firstname.lastname@example.org.