In a July 2018 study, researchers examined data from files of 511 gunshot victims kept by the Boston Police Department.
They found that weapon caliber — which refers to the diameter of the firearm barrel and is an indication of the diameter of the bullet — played a big role in how fatal shootings were.
People shot with medium-caliber weapons (.38, .380, and 9 mm) were more than twice as likely to die as those shot with small-caliber guns (.22, .25, and .32 mm). And victims shot with large caliber weapons (.357 magnum, .40, .44 magnum, .45, 10 mm, and 7.62 × 39 mm) were more than 4.5 times as likely to die as those shot with small-caliber firearms.
Replacing all large- and medium-caliber guns with small ones would have reduced the homicide rate by 39.5%, the researchers found.