<P> In order to keep track of the contestants' progress and relative standing throughout a race, split times (intermediate times) are taken at several points along the skiing track and upon finishing each shooting round . The large display screens commonly set up at biathlon arenas, as well as the information graphics shown as part of the TV picture, will typically list the split time of the fastest contestant at each intermediate point and the times and time differences to the closest runners - up . </P> <P> In the Olympics, all cross-country skiing techniques are permitted in the biathlon, allows the use of skate skiing, which is overwhelmingly the choice of competitors . The minimum ski length is the height of the skier minus 4 centimetres (1.6 in). The rifle has to be carried by the skier during the race at all times . </P> <P> The biathlete carries a small - bore rifle, which weighs at least 3.5 kilograms (7.7 lb), excluding ammunition and magazines . The rifles use . 22 LR ammunition and are bolt action or Fortner (straight - pull bolt) action . The rifle must weight more than 3.5 kilograms . Each rifle holds 4 magazines with 5 rounds each . Addtional rounds can be kept on the stock of the rifle for a relay race . </P> <P> The target range shooting distance is 50 metres (160 ft). There are five circular targets to be hit in each shooting round . When shooting in the prone position, the target diameter is 45 millimetres (1.8 in); when shooting in the standing position, the target diameter is 115 millimetres (4.5 in). On all modern biathlon ranges, the targets are self - indicating, in that they flip from black to white when hit, giving the biathlete, as well as the spectators, instant visual feedback for each shot fired . </P>

What caliber do they use in the biathlon in the olympics