Editing Base bleed (section)

{{short description|Method of increasing artillery range}}
{{More footnotes|date=November 2016}}
[[File:Base bleed artillery shell function.png|thumb|upright=1.35|Simplified diagram of a base-bleed artillery shell reducing turbulent vortices]]

[[File:Base bleed unit.png|right|thumb|Diagram of a base bleed unit. The top diagram shows the bottom of the shell and the location of the gas vents. The bottom diagram is a cut-away view showing the gas generator mechanism.]]

'''Base bleed''' or '''base burn''' '''(BB)'''<ref name=nguyen11>{{cite web |url=http://www.dtic.mil/ndia/2011gunmissile/Tuesday11528_Nguyen.pdf |title=M1128 Insensitive Munition High Explosive Base Burn Projectile |first=Ductri |last=Nguyen |publisher=Department of the Army |agency=Office of the Project Manager for Combat Ammunition Systems |date=30 August 2011 |access-date=7 April 2023 |archive-date=13 May 2015 |archive-url=https://web.archive.org/web/20150513030125/http://www.dtic.mil/ndia/2011gunmissile/Tuesday11528_Nguyen.pdf |url-status=bot: unknown }} {{PD-icon}}</ref> is a system used on some [[artillery]] shells to increase range, typically by about 20%–35%. It expels gas into the low-pressure area behind the shell to reduce [[Drag (physics)|base drag]] (but does not produce thrust, unlike [[rocket-assisted projectile|rocket-assisted projectiles]]). Being percentage-based, the range extension is more useful on longer-range artillery where an increase of approximately {{convert|5|-|15|km|mi}} can be achieved, and it also was found that the reduced turbulence gave the projectiles a more consistent trajectory, resulting in tighter grouping, and efficient shelling more than {{convert|40|km|mi}} away.

Base bleed technology was developed in Sweden in the mid-1960s but took some time to spread and find its niche between cheaper classical ordnance and even more expensive rocket-assisted projectiles. It is now a fairly common option.<ref>{{Cite web |title=155 mm HE ER FB-BB (OFd M3-DV) |author= |website=MSM GROUP |date= |access-date=29 July 2022 |url= https://www.msm.sk/en/what-we-do/defence/ammunition/artillery-ammo/155-mm-he-er-fb-bb-ofd-m3-dv/}}</ref><ref>{{Cite conference|url=https://asat.journals.ekb.eg/article_25665_987e8a5fd08bf4dd1b97a1fcd8a2c2fd.pdf |archive-url=https://web.archive.org/web/20190429105945/https://asat.journals.ekb.eg/article_25665_987e8a5fd08bf4dd1b97a1fcd8a2c2fd.pdf |archive-date=2019-04-29 |url-status=live|title=ASSESSMENT OF ERFB-BB PROJECTILE|first1=HASSAN|last1=YAKOUT|first2=MOHAMED S.|last2=ABDEL-KADER|publisher=MILITARY TECHNICAL COLLEGE|location=CAIRO, EGYPT|date=14–16 May 1991|conference=FOURTH ASAT CONFERENCE|id=MF-366}}</ref>