Beehive may refer to either of two forms of ammunition: a World War II-era combined shrapnel and incendiary anti-aircraft round (known as a Sanshiki) used by the Imperial Japanese Navy, or a Vietnam war era anti-personnel round packed with metal flechettes fired from an artillery gun most popularly deployed during that conflict.
The 460 mm (18 in) round weighed 2,998 lb and was filled with 900 incendiary tubes and 600 steel stays. The round was equipped with a delay fuze set before firing that detonated the shell at the set altitude; on explosion, the steel stays and the incendiary tubes were ejected in a 20-degree cone forward, with the shell fragments from the explosion itself further increasing the amount of debris. The incendiary tubes ignited about a half-second later and burned for five seconds with 16-foot long flames. Each of the incendiary tubes was a 90 mm long, 25 mm diameter hollow steel cylinder, filled with rubber thermite (phosphorus, vulcanized rubber, natural rubber, stearic acid, sulphur and barium nitrate) and ignited through holes on both sides. The rounds were similar to conventional shells, except for their wood-filled ogive and several layers of assembled fragments.
The blast of the main guns turned out to disrupt the fire of the smaller antiaircraft guns, so the 460 mm rounds were not successful. The copper drive bands of the rounds were poorly machined, and constant rapid fire was damaging to the gun rifling.
The 406 mm (16 in) round contained 1,200 incendiary tubes and on explosion burst into 2,527 fragments. By contrast a 460 mm round burst into 2,846 fragments.
The 203 mm (8 in) round weighed 125.86 kg and contained 255 incendiary tubes and a 2 kg burst charge in its base. It used the 91 Shiki delay fuze. Its maximum altitude was 10,000 m and it was reached after 55 seconds of flight. The burst charge scattered the fragments in a 12 degree cone. The maximum effective distance from the shell burst was about 1,000 meters, where the fragments reached dispersion diameter of 100 meters.
A 127 mm (5 in) round contained 66 incendiary tubes and had a 10 degree dispersion angle with dispersion diameter of 54 meters.
The first round actually termed "beehive" (for the 'buzzing' sound its darts made when flying through the air) was the M546 anti-personnel tracer (APERS-T), first fired in combat in 1966 and thereafter used extensively in the Vietnam War. Intended for direct fire against enemy troops, the M546 was direct fired from a near horizontally leveled 105 mm howitzer and ejected 8000 flechettes during flight by a mechanical time fuze.
Subsequently it was reported that the USSR had developed similar rounds for 122 mm and 152 mm artillery for use in indirect fire.
- Canister shot (or case-shot)
- Thomas J. Cutler (14 October 2013). The Battle of Leyte Gulf: 23-26 October 1944. Naval Institute Press. pp. 146–. ISBN 978-1-55750-243-8.
- Major General David Ewing Ott. FIELD ARTILLERY, 1954-1973. Department of the Army. Washington D.C., 1975.
- M546 APERS-T 105-mm
- ONTOS, the world's biggest shot gun