Authorities said one piece of shrapnel struck Pressley, severing his leg from below the knee, according to ABC affiliate WSB-TV.
The graphic video, recorded last week, captures blood splattering across the camera’s lens before Pressley yells, “I blew my leg off!”
Another voice says, “Call an ambulance!”
Pressley’s friends fashioned a tourniquet around his leg and drove him closer to the road, where he was picked up by authorities. He was eventually airlifted to a local hospital and was expected to recover, police said.
Lydiah Mays, one of Pressley’s neighbors, told WSB-TV that she heard the gunshots but wasn’t concerned until she heard the explosion, which shook her nearby home.
“I heard him scream, and so I came downstairs and we were all like looking out the front window,” Mays said. “You would’ve had to be on drugs or something to think it was a good idea to play with that and try to blow up a lawn mower.”
Tannerite — a mixture of ammonium nitrate and aluminum powder that explodes when struck by a high-velocity bullet — is normally used for target practice. The product’s website instructs users not to place Tannerite inside, under or near any type of metal objects. For every pound of Tannerite, experts advise standing 100 yards away.
“Do not shoot targets larger than 1 pound unless it is required due to extreme long-range competition,” safety instructions on the Tannerite website read.
Police say Pressley used three pounds of the material and was only 25 yards away when the explosion occurred.
“It has become extremely popular in the last couple of years, and is sold in many outdoor supply stores such as Cabelas, Bass Pro Shops, Gander Mountain, and others,” Battalion Chief Craig League with Walton County Fire Rescue told the Loganville News. “One of the drawbacks with Tannerite is that the more of the product that you mix together and shoot the bigger and louder the explosion. This makes it quite dangerous for amateur use.”
“To my knowledge, this is the first injury that we have encountered in Walton County from the use of exploding targets,” he added.
Sheriff Joe Chapman told NBC affiliate WXIA that he gets several complaints a week about Tannerite frightening people’s animals and waking children. He said that people are well within their rights to use the material on their own property but that they should ensure they have adequate space to do so safely.
The station reported that people have begun posting videos online of explosions that use as much as 100 pounds of Tannerite.
“Be careful,” Chapman said. “It’s very dangerous, it’s not a toy. It’s much more than a firecracker.”