A customer looks at a SIG Sauer hand gun at a gun show held by Florida Gun Shows, Saturday, Jan. 9, 2016, in Miami. President Barack Obama announced proposals this week to tighten firearms sales through executive action. (AP Photo/Lynne Sladky)

AURORA | The lethality of gunshot wounds is increasing despite steady advances in trauma care, according to a new study from researchers at the Anschutz Medical Campus in Aurora.

The report’s author, Angela Sauaia, professor of Public Health and Surgery at the Colorado School of Public Health, said the steadily climbing mortality rates aren’t a matter of shooters becoming better shots. Instead, they are simply firing more rounds.

“It’s not accuracy. It’s more bullets, they have more rounds,” she said. “Instead of shooting once or twice now they can shoot five times in a very short time interval.”

The study, which was published last month in the Journal of the American Medical Association, followed gunshot victims treated at Denver Health Medical Center from 2000 to 2013. Over that period, mortality rates from gunshots climbed about 6 percent while mortality rates from injuries like falls and car accidents fell.

Gunshots can be especially difficult for doctors, she said. If a patient comes to the hospital with a wound to the head and legs, she said, that requires an orthopedic specialist as well as a neurologist, which makes treatment challenging.

Sauaia said this study is unique because it looks at not only hospital data, but also data from the medical examiner’s office. That’s crucial, she said, because many people killed by gunfire die without ever reaching a hospital.

“People are shot and left to die in the street, people don’t call 911 after shooting somebody,” she said.

Still, Sauaia said, the study doesn’t tell the whole picture. Researchers weren’t able to track the caliber of weapon used, the size of the magazine or other details about the severity of injuries caused by specific firearms.

But a study like that would take money and time, she said, and unlike other researchers, gun violence researchers can’t tap the same pool of federal money. Congress in 1996 effectively barred the Centers for Disease Control from studying gun violence and Sauaia said that makes funding research like hers tough.

In this study, the Colorado School of Public Health — which is based at the Anschutz campus — funded the research, she said, and some researchers donated their time on the weekends.

“If we don’t have funding it’s difficult to sustain a study for two or three years until we can get all of the data sets together,” she said.

But David Kopel, a gun rights advocate and researcher at the Independence Institute, said there has been a flood of private money into gun violence research in recent years, including from former New York Mayor Michael Bloomberg.

Kopel said the School of Public Health study leaves out whether the shootings it studied were justifiable acts of self defense or criminal shootings. And, he said, while severity may have increased, gun violence around the country dropped during the 13 years the study examined.

As for gun research, Kopel said despite the limitations on what the CDC can study, research continues.

“Firearms is certainly an issue worthy of social science study. Criminologists, sociologists, econometricians, legal scholars, historians, public health and medical researchers have been writing scholarly articles on the topic for decades,” he said in an email.

But Sauaia said the research remains more difficult than other types, and that means young researchers shy away from it.

Since the study came out last month she said she has already received hate mail.

“Not many people researching cardiology or nephrology will receive hate mail,” she said.