of the case forward of the cut, creating a 'cut-shell'. This can be dangerous, as it is thought to cause higher chamber pressures—especially if part of the shell remains behind in the barrel and is not cleared before another shot is fired. Wider patterns Shooting the softest possible shot will result in more shot deformation and a wider pattern. This is often the case with cheap ammunition, as the lead used will have minimal alloying elements such as antimony and be very soft. Spreader wads are wads that have a small plastic or paper insert in the middle of the shot cup, usually a cylinder or "X" cross-section. When the shot exits the barrel, the insert helps to push the shot out from the center, opening up the pattern. Often these result in inconsistent performance, though modern designs are doing much better than the traditional improvised solutions. Intentionally deformed shot (hammered into ellipsoidal shape) or cubical shot will also result in a wider pattern, much wider than spherical shot, with more consistency than spreader wads. Spreader wads and non-spherical shot are disallowed in some competitions. Hunting loads that use either spreaders or non-spherical shot are usually called "brush loads", and are favored for hunting in areas where dense cover keeps shot distances very short. Spread Most shotgun shells contain multiple pellets in order to increase the likelihood of a target being hit. A shotgun's shot spread refers to the two-dimensional pattern that these projectiles (or shot) leave behind on a target. Another less important dimension of spread concerns the length of the in-flight shot string from the leading pellet to the trailing one. The use of multiple pellets is especially useful for hunting small game such as birds, rabbits, and other animals that fly or move quickly and can unpredictably change their direction of travel. However, some shotgun shells only contain one metal shot, known as a slug, for hunting large game such as deer. As the shot leaves the barrel upon firing, the three-dimensional shot string is close together. But as the shot moves farther away, the individual pellets increasingly spread out and disperse. Because of this, the effective range of a shotgun, when firing a multitude of shot, is limited to approximately . To control this effect, shooters may use a constriction within the barrel of a shotgun called a choke. The choke, whether selectable or fixed within