36 range. The calibre and velocity of the projectiles, as well as the materials they are composed of, will also affect the likelihood and seriousness of injury. 7.5.4 Certain projectiles are highly inaccurate.109 To meet international standards, impact projectiles should be capable of striking an individual to within a 10-centimetre diameter of the targeted point when fired from the designated range. Skip-firing projectiles off the ground causes an unacceptable risk of serious injury due to their inaccuracy. CIRCUMSTANCES OF POTENTIALLY UNLAWFUL USE 7.5.5 Kinetic impact projectiles should not be fired in automatic mode. 7.5.6 Multiple projectiles fired at the same time are inaccurate and, in general, their use cannot comply with the principles of necessity and proportionality. Metal pellets, such as those fired from shotguns, should never be used. 7.5.7 Kinetic impact projectiles must be tested and authorized to ensure that they are sufficiently accurate to strike a safe area on a human-sized target from the required distance, and without excessive energy, which could cause injury.110 7.5.8 Kinetic impact projectiles should not be targeted at the head, face or neck. Rubber-coated metal bullets are particularly dangerous and should not be used.111 A. Mahajna et al., “Blunt and penetrating injuries caused by rubber bullets during the IsraeliArab conflict in October, 2000: a retrospective study”, The Lancet, vol. 359, No.  9320 (2000), pp. 1795–1800. 110 Amnesty International and Omega Research Foundation, The Human Rights Impact of Less Lethal Weapons and Other Law Enforcement Equipment, p. 138; R.J. Haar and V. Iacopino, Lethal in Disguise: The Health Consequences of Crowd-Control Weapons. Network of Civil Liberties Organizations and Physicians for Human Rights, 2016 (available at http://bit.ly/2FBbxmA), p. 24. 111 The Department of Peacekeeping Operations prohibits the use of rubber bullets by United Nations police personnel, because of the risks of serious injury or even death from their improper use. United Nations, United Nations Peacekeeping Missions Military Police Manual, July 2015, para. 3.6.1. 109