Peru
Practice Relating to the Use of Prohibited Weapons
Peru’s IHL Manual (2004) states: “Combatants must not modify their weapons without authorization or use them for any purpose other than their intended use.” 
Peru, Manual de Derecho Internacional Humanitario para las Fuerzas Armadas, Resolución Ministerial Nº 1394-2004-DE/CCFFAA/CDIH-FFAA, Lima, 1 December 2004, § 26.a.
Peru’s IHL and Human Rights Manual (2010) states: “Combatants must not modify their weapons without authorization or use them for any purpose other than their intended use.” 
Peru, Manual de Derecho Internacional Humanitario y Derechos Humanos para las Fuerzas Armadas, Resolución Ministerial No. 049-2010/DE/VPD, Lima, 21 May 2010, § 27(a), p. 236.