A sniper rifle is much more accurate than a normal rifle. Almost all sniper rifles use a sniper scope, a special telescope that allows them to see targets very far away. There are two different kinds of sniper rifles: bolt action rifles, which fire a single shot and then the user must ready the next shot, and semi-automatic ("semi-auto") rifles which fire a single shot each time the trigger is pulled, and automatically ready the next shot for firing. Fully automatic rifles, which fire continuously when the trigger is pulled as long as there is ammunition, generally are not used though in rare instances they can be converted into a sniper rifle. In one such instance, a heavy machine gun with a scope, while not a true sniper rifle, set the record for longest kill by a sniper for years, until advances in rifle technology and sniper training allowed a sniper with a true sniper rifle to beat that record.