Video footage posted online shows the man wearing what appears to be a Hi-Viz vest belonging to the Polish Sports Shooting Association (PZSS) at the event in Godawy, western Poland.
As he talks to another man in a similar vest, he points what appears to be a hunting rifle at the 70-year-old victim before pulling the trigger.
The victim is then seen collapsing to the ground and swearing as he rolls around in pain.
PZSS spokesman Włodzimierz Gałecki has since denied that the association has any connection to the shooter.
He told the daily Fakt newspaper: “This event had nothing to do with the activities of the Polish Shooting Sports Association.
“If this is a shooting position, then the competition participant has no right to behave in such a way that they are standing around, waving this weapon in all directions.
“The vests that can be seen in the recording, marked as PZSS, are some kind of fake, homemade work.
“It looks like a vest that you carry in a car, with inscriptions on it. Our vests are based on the vests of the International Rifle Federation, the International Shooting Sports Association and they look slightly different.
“There are photos and videos from our competitions on the Internet, showing how our judges are equipped, and what the shooting range looks like in general.”
Police spokesman Michał Robakowski said: “A 68-year-old man was charged with unintentionally exposing a 70-year-old man to direct danger of loss of life or health and unintentionally causing medium damage to his health.
“According to expert opinion, the injured party suffered injuries that required more than seven days of treatment.”
