Bushmaster IV

{{Infobox weapon

| name = Bushmaster IV

| image =

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| origin = United States

| type = Chain-driven autocannon

| is_ranged = yes

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| designer = Alliant Techsystems

| design_date =

| manufacturer = Alliant Techsystems

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| weight = Receiver: {{convert|198|kg|lb|lk=on|abbr=on}}
Feeder: {{convert|29|kg|lb|abbr=on}}
Barrel: {{convert|138|kg|lb|abbr=on}}
Total: {{convert|365|kg|lb|abbr=on}}

| length = {{convert|4018|mm|in|lk=on|abbr=on}}

| part_length =

| width = {{convert|430|mm|in|abbr=on}}

| height = {{convert|478|mm|in|abbr=on}}

| cartridge = 40×365mmR

| action = Open bolt

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| feed = Linkless feed

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}}

The Bushmaster IV is a 40 mm chain-driven autocannon designed and built by Alliant Techsystems, based on the M242 Bushmaster, Bushmaster II and Bushmaster III.{{cite web|url=https://www.atk.com/products-services/40mm-bushmaster-iv-automatic-cannon/|title=40mm Bushmaster IV Automatic Cannon|archive-url=https://web.archive.org/web/20140402143531/http://www.atk.com/products-services/40mm-bushmaster-iv-automatic-cannon/|archive-date=2 April 2014|url-status=unfit}}{{cite web|url=http://www.armytimes.com/article/20131108/NEWS/311080016/Bigger-badder-Bushmaster-cannon-works |title=Bigger, badder Bushmaster cannon in the works |date=8 November 2013 |archive-url=https://archive.today/20131230091159/http://www.armytimes.com/article/20131108/NEWS/311080016/Bigger-badder-Bushmaster-cannon-works |archive-date=2013-12-30 |url-access=subscription |url-status=dead }} The Bushmaster IV fires 40×365mmR 3P (Prefragmented, Programmable, Proximity-fuzed), APFSDS-T Mk I, and APFSDS-T Mk II rounds. The 3P round will provide air burst capability and the APFSDS-T Mk II can penetrate armor with a thickness in excess of {{convert|150|mm|abbr=on}}.{{cite web|url=http://www.dtic.mil/ndia/2003gun/boren.pdf|title=Presentation of the Bofors 3P and System Concept|last=Borén|first=Michael|date=June 2002|format=PDF|access-date=30 December 2013|archive-url=https://web.archive.org/web/20130228164346/http://www.dtic.mil/ndia/2003gun/boren.pdf#|archive-date=28 February 2013|url-status=dead|df=dmy-all}}