In the video, David Pressley, 32, moves closer and closer to the unused lawnmower as he peppers it with bullets from a semi-automatic rifle.
Pressley and his friends had filled the lawn mower with three pounds of Tannerite, a binary explosive that can be purchased legally in Georgia and – when mixed – ignited by gunshot.
Shooters should be 100 yards (300 feet) away from their target per pound of Tannerite, local sheriff Joe Chapman told USA Today.
Pressley was just 14 yards (43 feet) away from the lawnmower when it exploded and a piece of flying shrapnel hit him, slicing his leg off below the knee.
In the gruesome footage, blood spatter hits the camera lense as Pressley yells: “I blew my leg off!” Another man shouts: “Call an ambulance!”
Many videos of people improperly using the explosive mix can be found online.
Sheriff Chapman says he receives several complaints about the explosive on a weekly basis, and released the graphic footage to demonstrate just how dangerous it is. “It’s not a toy,” he warned.