Airburst round

An airburst round is a type of tactical anti-personnel explosive ammunition, typically a shell or grenade, that detonates in midair, causing air burst effect fragment damage to an enemy.

Airburst effect from 40mm round on dummy soldiers

This makes it easier to hit enemy soldiers behind a wall, in a defensive fighting position, or in a confined space or room. It is used on many guns, from artillery to the hand-held XM25 Individual Airburst Weapon System (derived from the XM29 OICW). Unlike traditional grenades, such as the 40 mm grenade, smart grenades can be electronically programmed to explode after traveling a certain distance. A fire control computer or some other electronic sighting system is used to quickly program the electronic fuse with any distance, as conditions dictate.

Orbital ATK developed 30x173mm Mk310 PABM-T airburst rounds for Mk44 Bushmaster II.[1][2]