[jabl]

IIUC many military 5.56mm rounds are designed to fragment upon impact (against the spirit if not the letter of the Geneva convention). 7.62mm rounds are (or at least used to be) designed to hold together in one piece.

[ntw1103]

The latest military 5.56 rounds are actually steel, and designed for penetration, not fragmentation. The US army is now using M855A1(Steel core, and steel penetrating tip), which replaces the M855(jacketed steel core) What you are thinking of is the 1899 Hague Convention, not the Geneva convention. Also, the USA was not a signing country. https://www.army.mil/article/41283/army_begins_shipping_impr...

[bluedino]

A single soldier can also carry a heck of a lot more 5.56 than 7.62

Then there's the urban legend of 5.56 being chosen because injured troops are more of a liability than dead troops