In 2021 there were at least 144 incidents of gunfire on school grounds in the U.S., resulting in 28 deaths and 86 injuries nationally. https://everytownresearch.org/maps/gunfire-on-school-grounds/
When it comes to how American children are exposed to gun violence, gunfire at schools is just the tip of the iceberg – every year, more than 3,000 children and teens are shot and killed and 15,000 more are shot and injured. An estimated 3 million children in the US are exposed to shootings per year.
“A 14-year-old girl was shot and killed by her 13 year old brother, who was making and selling guns, Georgia sheriff says” https://www.cnn.com/2021/12/02/us/kyra-scott-14-year-old-killed-brother/index.html
“The use of ghost guns — self-assembled firearms that are often made with parts sold online and do not have serial numbers — has been on the rise in some major cities.
According to a Justice Department news release in May, between 2016 and 2020, more than 23,000 un-serialized firearms were reported to have been recovered by law enforcement from potential crime scenes.”
Eideard 
In 2021 there were at least 144 incidents of gunfire on school grounds in the U.S., resulting in 28 deaths and 86 injuries nationally. https://everytownresearch.org/maps/gunfire-on-school-grounds/
When it comes to how American children are exposed to gun violence, gunfire at schools is just the tip of the iceberg – every year, more than 3,000 children and teens are shot and killed and 15,000 more are shot and injured. An estimated 3 million children in the US are exposed to shootings per year.
“A 14-year-old girl was shot and killed by her 13 year old brother, who was making and selling guns, Georgia sheriff says” https://www.cnn.com/2021/12/02/us/kyra-scott-14-year-old-killed-brother/index.html
“The use of ghost guns — self-assembled firearms that are often made with parts sold online and do not have serial numbers — has been on the rise in some major cities.
According to a Justice Department news release in May, between 2016 and 2020, more than 23,000 un-serialized firearms were reported to have been recovered by law enforcement from potential crime scenes.”