They’re easy to use, but for real stopping power nothing beats a howitzer.
You are correct; bigger holes are better! If Emily wants something traditional and useful, she should get a Commander sized .45ACP. It is the 100th anniversary of the 1911 after all. Next best choice would be a .40S&W Springfield Compact XP. Otherwise, go for the gusto and see about an MP5. Don’t mess with Emily, she’s got a gun.