What Did This Guy Shoot (And Blow Up) In Jackpot?

Have you ever seen something that you don't completely understand and it bothers you until you figure it out? That's my deal. I've seen something and I have to know what this guy and his friends shot near Jackpot that caused a huge explosion.

I don't know if this dude is practicing to be a sniper or what he's trying to accomplish, but he starts the video laying on a towel with a scoped rifle. Then, at around the 13 second mark, he hits whatever he was shooting at and KABOOM!

This is what happens when rednecks are left alone on dirt roads in Nevada.

I will give him credit. That was a big boom and the guy part of me that appreciates big booms approves. BUT, I have to know what he shot.

Can you solve this redneck mystery? Was it a bag of fertilizer or an unsuspecting clown? Or, maybe a clown holding a bag of fertilizer? Please answer if you know so the redneck part of me can put this question to rest.

UPDATE: Have had some listeners suggest that it's probably a bag of Tannerite.