Not a mass shooting, but always nice to see a pro gun nut offed by his own weapon, especially when it's self inflicted and hilarious like this. A Darwin awards winner.
https://www.msn.com/en-gb/news/world/pro-gun-lawyer-shot-with-own-weapon-by-mri-scanner-dies/ar-AA17kTYH?ocid=msedgntp&cvid=69741328e88a4aa9b8a7eceecf1ca4d4