Mexico
Practice Relating to Rule 77. Expanding Bullets
Mexico’s Army and Air Force Manual (2009) states: “It is prohibited to use … bullets that expand or flatten easily in the human body, such as bullets with a hard envelope which does not entirely cover the core or is pierced with incisions (dum-dum bullets).”
In 2009, Mexico submitted a proposal to the UN Secretary General to amend Article 8(2)(c) of the 1998 ICC Statute in accordance with Article 121(1) of the Statute, stating:
Within the category of serious violations of the laws and customs applicable in international armed conflicts, the use of certain weapons whose effects are of an indiscriminate nature or cause superfluous injury or unnecessary suffering is included. Such weapons are … bullets which expand or flatten easily in the human body. The use of these … kinds of weapons is prohibited by conventional and customary international law.

[footnotes in original omitted]