exceptions (such as the Olympic Games and the ISSF World Cups). A shooter remains a junior up to and including the calendar year in which he or she becomes 21 years of age, although a junior may opt to participate in the main class instead. There are also ISSF Junior World Cups. In both the qualification stage and the final stage, all shooting is supervised by a Chief Range Officer, whose duties include responsibility for the correct behaviour of all personnel, dealing with technical irregularities, and cooperation with the jury. Qualification For the qualification stage, the shooters are divided as necessary into relays. Each relay starts with a 15-minute preparation time during which the shooter may fire an unlimited number of sighting shots. Afterwards, the Chief Range Officer gives the command "match firing, start", indicating the start of the competition time. 60 competition shots must be shot within a 75-minute period time (90 minutes if no electronic targets are available). The 60 shots are usually organized in 6 ten-shot series for display on scoreboards. Final The top eight shooters in the qualification round advance to the final. Often, many shooters have the same score. The higher number of inner tens is the first tiebreaker. If two or more shooters have the same amount of inner tens, the shooter with the highest score in the last ten-shot series is placed higher. During the final, the score zones are divided into tenths (by means of a special gauge, in the absence of automatic scoring devices), so that each hit can give up to 10.9 points instead of the maximum 10 during the qualification. Electronic targets are required by the ISSF for finals at the Olympic Games, ISSF World Cups and ISSF World Championships. After a five-minute sighting shot period and the presentation of the athletes to the audience, the athletes have 250 seconds to shoot five shots after the command "for the first competition series, load, start". The same command is given again for a second five shot series. After the tenth shot, separate commands are given for each competition shot with a time limit of 50 seconds per shot. After each two shots, the athlete with the lowest score is eliminated until two shooters are left to compete for the first place in the 23rd and 24th shot. Current rules were introduced in 2017 after the 2016 Summer Olympics. History The