Editing Gyrojet (section)

{{Short description|Obscure prototype weapon firing gyroscopic rockets in the 1960's.}}
{{Infobox weapon
| name               = Gyrojet
| image              =
| image_size         = 300px
| caption            = Gyrojet Mark I
| origin             = United States
| type               = [[Small arms]] ([[rocket launcher]])
<!-- Type selection -->| is_ranged          = YES
| is_missile         = YES
<!-- Service history -->| used_by            = [[Military Assistance Command, Vietnam – Studies and Observations Group]]
| wars               = [[Vietnam War]]
<!-- Production history -->| designer           = {{plainlist|
*Robert Mainhardt
*Art Biehl}}
| manufacturer       = MB Associates
| unit_cost          = {{plainlist|
*$300 (1968)
*>$1000 (2025)}}
| production_date    = 1962 - 1975
| number             = less than 2000 globally
| variants           = See [[#Variants|Variants]]
<!-- General specifications -->| weight             = {{convert|0.88|lb|kg|abbr=on}}
| length             = {{convert|10.88|in|cm|abbr=on}}
| part_length        = {{convert|5|in|cm|abbr=on}}
<!-- Ranged weapon specifications -->| cartridge          = {{plainlist|
*MKI: 13mm rocket
*MKII: 12mm rocket
*AR: 6mm rocket}}
| caliber            = {{plainlist|
*MKI: .51 caliber
*MKII: .47 caliber
*AR: .24 caliber}}
| action             = Blowback
| rate               = {{plainlist|
*60 [[Rate of fire|RPM]]
*Select fire (assault rifle variant)}}
| velocity           = Very low, but increasing over trajectory to about 1250 fps
| range              = {{convert|55|yd|m}}
| feed               = 6-round internal box magazine (main variants)
| sights             = [[Iron sight]]s
}}

The '''Gyrojet''' is a family of unique [[firearm]]s developed in the 1960s named for the method of [[gyroscope|gyroscopically]] stabilizing its projectiles.<ref>https://americansocietyofarmscollectors.org/wp-content/uploads/2022/04/2012-B105-MBA-Gyrojet-Mark-I-Model-B-Pistols-and-C.pdf {{Bare URL PDF|date=May 2025}}</ref> Rather than inert [[bullets]], Gyrojets fire small [[Rocket (weapon)|rocket]]s called Microjets which have little recoil and do not require a heavy barrel or chamber to resist the pressure of the combustion gases. Velocity on leaving the tube was very low, but increased to around {{convert|1250|ft/s}} at {{convert|30|ft}}.<ref>{{cite web | url=https://www.recoilweb.com/the-gyrojet-in-this-case-it-is-rocket-science-169153.html | title=The Gyrojet: In This Case, It is Rocket Science | date=22 July 2021 }}</ref> The result is a very lightweight and transportable weapon.<ref>{{cite web |url=http://biskun.com/hobby/firearm/gyrojet.html |title= MBA Gyrojet Pistol|website=biskun.com |archive-url=https://web.archive.org/web/20100412135119/http://biskun.com/hobby/firearm/gyrojet.html |archive-date=April 12, 2010}}</ref>

Long out of production, today they are a coveted collector's item with prices for even the most common model ranging above $1,000. They are rarely fired; ammunition is scarce and can cost over $200 per round.<ref name="svevap">{{cite web|url=http://www.svevap.se/index.php?option=com_content&task=view&id=13&Itemid=27|title=Svenska Vapensamlarföreningen, SVEVAP - Gyrojet|publisher=svevap.se|access-date=2015-09-03}}</ref>