The same thing happened to me.
I was sitting on a bench behind station four watching a squad on station one shoot, when I felt a sting in my left upper arm, I looked and there was blood running down my arm, I had to pry a pellet out with a knife blade. The pellet was flattened on one side. The shooter was shooting high one and broke the target about over the stake. that pellet had to have turned 90 degrees to hit me and must have bounced off the target.
Pete