Simple.
Of the thirteen, one was shot with a handgun in a drug deal gone bad, the other committed suicide with a pistol.
Number three was killed with a shotgun.
Four committed suicide with a semi-automatic rifle.
Five was accidentally shot with an "assault weapon."
Six was out hunting, and was shot by accident by another hunter using an Etron-X electronically fired rifle.
Seven was murdered with a sniper rifle.
Eight accidentally shot himself with a lever-action rifle.
Nine was gunned down by an MP5 submachine gun in a no-knock drug raid gone bad.
Ten accidentally shot his friend with a muzzleloading rifle.
Eleven was out hiking and wandered by accident into a military training range, and was eviscerated by a 40mm rifle grenade.
Twelve was "disappeared" by the GSG-9 because he was the youngest suspected member of al-Qaeda, he was eliminated with a G11-ACR firing 4.92x34mm caseless ammunition.
Thirteen was accidentally killed when an A-10 Thunderbolt (known commonly as the "Warthog") heading to Afghanistan lost an engine and fell out of the sky, the GAU autocannon landed on the poor girl's head, killing her instantly.
So there you have it: thirteen kids, 12 different kinds of guns. And this happens every day! Well, some days it's historical cannons, other days it's full auto machineguns, usually it's only about 8 kids killed a day by exotic weapons. But every few weeks, a howitzer shell takes out twenty or thirty of them at a time, which brings the average back up. And that's how they arrive at the 13/day figure.
The other 10.7 of the thirteen are suicides. .3 are accidents. VPC had a major foulup in their propaganda effort when they let this one through. Usually they are very careful to inflate their numbers with the suicides, and very careful to imply that all of the deaths are accidents.
This is very strange. Perhaps the person who did this study has some residual honesty.
Don't forget that at least once a year, those Civil War re-enactors' flitlocks go wild and massacre some chillldrun.
Didn't some kid fall off of a memorial cannon and die, a few years back? There was one "gun death" right there...
I can't have my first cocktail of the day until I hear news of the daily black-powder musket child shooting.