bullet, increases penetration, and can help prevent it from leaving deposits of lead inside the bore. In controlled expansion bullets, the jacket and other internal design characteristics help to prevent the bullet from breaking apart; a fragmented bullet will not penetrate as far. Accuracy For bullets designed for target shooting, some such as the Sierra "Matchking" incorporate a cavity in the nose, called the meplat. This allows the manufacturer to maintain a greater consistency in tip shape and thus aerodynamic properties among bullets of the same design, at the expense of a slightly decreased ballistic coefficient and higher drag. The result is a slightly decreased overall accuracy between bullet trajectory and barrel direction, as well as an increased susceptibility to wind drift, but closer grouping of subsequent shots due to bullet consistency, often increasing the shooter's perceived accuracy. The manufacturing process of hollow-point bullets also produces a flat, uniformly-shaped base on the bullet which allegedly increases accuracy by providing a more consistent piston surface for the expanding gases of the cartridge. Testing Terminal ballistics testing of hollow point bullets is generally performed in ballistic gelatin, or some other medium intended to simulate tissue and cause a hollow point bullet to expand. Test results are generally given in terms of expanded diameter, penetration depth, and weight retention. Expanded diameter is an indication of the size of the wound cavity, penetration depth shows if vital organs could be reached by the bullet, and weight retention indicates how much of the bullet mass fragmented and separated from the main body of the bullet. How these factors are interpreted depends on the intended use of the bullet, and there are no universally agreed-upon ideal metrics. Legislation The Hague Convention of 1899, Declaration III, prohibited the use in international warfare of bullets that easily expand or flatten in the body. It is a common misapprehension that hollow-point ammunition is prohibited by the Geneva Conventions, as the prohibition significantly predates those conventions. The Saint Petersburg Declaration of 1868 banned exploding projectiles of less than 400 grams, along with weapons designed to aggravate injured soldiers or make their death inevitable. Despite the widespread ban on military use, hollow-point bullets are one of the most common types of bullets used by civilians and police, which is due largely to the reduced risk of bystanders being hit by over-penetrating or ricocheted bullets, and the increased speed of incapacitation. In