During World War II a "proximity fuze" was developed for antiaircraft use, controlled by a Doppler radar device within the shell that caused it to explode when near the target.
[3] Some anti-personnel bounding mines such as Germany's World War II "Bouncing Betty" fire a grenade into the air, which detonates at waist level, increasing the blast radius and harm inflicted by detonation, shock wave, and flying splinters.
Grenade launchers using this technology include the XM29, XM307, PAPOP, Mk 47 Striker, XM25, Barrett XM109, K11, QTS-11, Norinco LG5 / QLU-11, and Multi Caliber Individual Weapon System.
[7] In conventional warfare, air bursts are used primarily against infantry in the open or unarmored targets, as the resulting fragments cover a large area but will not penetrate armor or field fortifications.
Set properly, the shell would detonate approximately 10 meters (33 feet) above the ground at ranges of 200 to 1,000 m (660 to 3,280 ft).
[citation needed] Killers Junior and Senior were developed as alternatives to the Beehive flechette rounds previously used against nearby enemy troops.