News There are currently 15 shooting events in the Olympic Games, spread across three different classes of gun: pistol, rifle and shotgun Which ever event they are taking part in, competitors at the test event in Rio de Janeiro this week say that the fine-tuning of their equipment can make the difference between Olympic glory and failure  “For me, it is the same as a Formula 1 car” Brazilian shooter Bruno Heck on his rifleAs in elite-level motor racing, it is not just cool heads and quick thinking that are required Continuous, millimetric adjustments to changing conditions play just as important a part in success  Competitors use guns with customised butt plates and cheek-pieces; during the 50m three positions rifle event, they have to use different butt plates for each shooting position – kneeling, prone and standing  Become a shooting expert with our interactive infographicHeck is one of almost 700 athletes from 88 countries who have come to Rio to participate in the third stage of the 2016 World Cup series The International Shooting Sport Federation (ISSF) competition, which is doubling up as the Rio 2016 test event at the Olympic Shooting Centre in Deodoro Olympic Park, runs until Sunday (24 April)  The event is also helping determine which competitors return to the city for the Olympic Games in August In the 10m and 50m rifle events, athletes have to make tiny changes to their sights (Photos: Getty Images)In total, there are five rifle events in the Olympic Games  In all the events, shooters have to make fine adjustments to their sights for wind and elevation Athletes are also allowed to use colour filters to improve their sighting of the target Each competitor alters the filter as they prefer, depending on changing light and weather conditions  “Any movement changes the entire feeling of a gun”Bruno Heck, Brazilian rifle competitorIn the pistol competition, athletes use customised grips on their guns Brazilian competitor Júlio Almeida says that while the grips are all made of wood, athletes can mould and sand the shape to fit their hands better As with the rifle, athletes need to adjust their equipment for wind and elevation Competitors can only fire with one hand and always from a standing position There are five Olympic events for pistol A particular problem for pistol competitors is that over the course of their event, their hands can change shape “If it's hot, the hand swells Often during a competition the hand will swell in size”Júlio Almeida, Brazilian pistol competitorAir pistols for the quick fire 10m and 50m events have bespoke grips for each competitor (Photo: Getty Images)In the trap and skeet events, competitors must stand outside and shoot with 12-bore shotguns at clay targets propelled in varied directions Traps and skeets use a different layout of machines for launching the targets  Today's targets are bright orange and are not made of clay but of a mixture of ecological materials They also contain a powder to make them more visible when they are hit Brazilian shotgun specialist Emanuel Munarretto says that as well as the light and the wind, the heat can also have a major influence on an athlete's performance “We spend at least 30 minutes in the sun and because of television we can't use a sunshade or umbrella”Emanuel Munarretto, Brazilian shotgun competitorCompetitors in the trap and skeet events can use coloured lenses to improve their view of the targets Many also use ear protectors; Munarretto puts a jelly in his ears to protect them from noise As with the other classes of gun, athletes prefer bespoke butts that are specially designed for the form of their shoulders and cheeks In the traps and skeets events, competitors use 12-bore shotguns to hit moving targets (Photos: Getty Images)There is also a wide variety of clothing on show at the Olympic Shooting Centre in Deodoro this week Shooters in the three positions event for rifles make rapid adjustments to their clothing for each different shooting position, so comfortable and practical clothes are a must  Results from RioExperienced competitors in the early events in Rio had some problems in adapting to the local conditions in the Olympic Shooting Centre Júlio Almeida finished in 26th position in the 10m air pistol event The star of the Brazilian side, 23-year old Felipe Wu, who won the 10m gold in the air pistol at the ISSF Rifle and Pistol World Cup in Bangkok, only managed 16th position Even South Korean Jin Jong-Oh, three-time Olympic champion and double world record holder, struggled to perform and finished 12th “We all felt the same thing,” he said “We will have to work hard ”The champion in the 10m air pistol event, Pablo Carrera of Spain, said competitors were concerned above all by the heat and noise The ISSF has allowed more music and more reaction from spectators in Rio than is customary in other shooting competitions  “It was good to come here to see how we will have to look after our hydration because of the heat”Pablo Carrera, winner of the 10m air pistol men eventThe three position 50 metre event makes unique demands on rifle specialists (Photo: Getty Images)Alberto Fernandez won Spain's second gold medal in Rio by triumphing in the trap event for men In the women's 10m air pistol final, two-time Olympic medallist Olena Kostevych of Ukraine won gold Lin Yi Chun of Chinese Taipei defeated Lebanon’s Ray Bassil in the trap event for women Du Li of China beat Daria Vdovina of Russia to first place in the 10m air rifle final for women