High-explosive incendiary

{{Short description|Type of ammunition}} In warfare, '''high-explosive incendiary''' ('''HEI''') is a type of ammunition specially designed to impart energy and therefore damage to its target in one or both of two ways: via a high-explosive charge and/or via its incendiary (fire-causing) effects. Each round—by definition—has both capabilities.<ref>{{cite book |last1=Lee |first1=R. Geoffrey |title=Defence Terminology |date=1991 |publisher=Brassey's (UK) |isbn=978-0-08-041320-4 |page=95 |url=https://www.google.co.uk/books/edition/Defence_Terminology/B1zfAAAAMAAJ |language=en}}</ref>

HEI ammunition is fused either mechanically or chemically. The armor-piercing ability can vary widely, allowing for more focused fragmentation or larger scatter.{{cn|date=March 2026}}

==History== HEI ammunition was originally developed for use in large-caliber cannon, howitzer and naval artillery.{{Citation needed|date=March 2025}} Currently, HEI rounds are most commonly made in medium-caliber sizes of 20, 25, 30, and 35 mm. They are fired from various platforms, including aircraft, anti-aircraft cannons, and anti-missile systems.{{cn|date=March 2026}}

HEI ammunition has also been used on the battlefield against tanks and other armored vehicles, but mostly in a last ditch attempt to disable external components. {{cn|date=March 2026}}

==Uses== thumb|The shell on the left is a 30 mm HEI HEI rounds are mainly used in incendiary rounds against softer targets such as aircraft, infantry, and unarmored vehicles.{{cn|date=March 2026}}

==See also== * High explosive incendiary/armor piercing ammunition (HEIAP) * Mine shell * Raufoss Mk 211

==References== {{reflist}}

==External links== {{commons|Ammunition}} *[https://web.archive.org/web/20011125094806/http://www.dtic.mil/ndia/2001gun/Tasson1.pdf Live fire experiment of mechanically fuzed HEI rounds] *[http://www.fas.org/man/dod-101/sys/land/pgu-13.htm Example of US military 30 mm HEI round] *[https://www.nammo.com/product/our-products/ammunition/medium-caliber-ammunition/35-mm-series/35-mm-x-228-hei-sd-and-hei-t-sd/ Example of NATO 35×228mm HEI round] from Nammo *[https://web.archive.org/web/20040214230828/http://history.amedd.army.mil/booksdocs/wwii/actvssurgconvol2/chapter4figure140.jpg Fragmentation pattern of a German Round]

Category:Artillery ammunition Category:Anti-tank rounds Category:Explosive_weapons Category:Incendiary weapons