View source for Advanced Combat Optical Gunsight

{{short description|American series of telescopic sights manufactured by Trijicon}}
[[File:PEO Trijicon M150 RCO.jpg|thumb|upright=1.3|TA31RCO variant of the ACOG which is designated as the M150 RCO in [[United States Army]] service]]

The '''Advanced Combat Optical Gunsight''' ('''ACOG''') is a series of [[Prism sight|prismatic telescopic sights]] manufactured by [[Trijicon]]. The ACOG was originally designed to be used on the [[M16 rifle]] and [[M4 carbine]], but Trijicon has also developed ACOG accessories for other firearms. Models provide fixed-power [[magnification]] levels from 1.25× to 6×.<ref>{{cite web |url=http://www.trijicon.com/na_en/products/product1.php?id=ACOG |title=Official Listing of ACOG models |access-date=2011-02-11 |archive-url=https://web.archive.org/web/20110204142409/http://www.trijicon.com/na_en/products/product1.php?id=ACOG |archive-date=2011-02-04 |url-status=dead }}</ref> ACOG [[reticle]]s are illuminated at night by an internal [[tritium]] [[phosphor]]. Some versions have an additional daytime reticle illumination via a passive external [[fiberoptic]] [[light tube|light pipe]] or are [[LED]]-illuminated using a [[dry cell|dry battery]]. The first ACOG model, known as the TA01, was released in 1987.<ref>{{Cite web|title=Acog History|url=https://www.trijicon.com/our-story/trijicon-history|website=Trijicon Acog.com}}</ref>

==History==
The first ACOG model, known as the TA01, was released in 1987.<ref>{{cite web|url=http://www.trijicon.com/na_en/products/product3.php?pid=TA01|archive-url=https://web.archive.org/web/20110913072623/http://www.trijicon.com/na_en/products/product3.php?pid=TA01|url-status=dead|archive-date=13 September 2011|title=TA01 ACOG - Trijicon, Inc.|date=13 September 2011}}</ref><ref>{{cite web|url=https://www.millionthacog.com/history/|archive-url=https://web.archive.org/web/20170922031015/https://www.millionthacog.com/history/|url-status=usurped|archive-date=22 September 2017|title=Trijicon 24 Days of ACOG Sweepstakes|website=www.millionthacog.com|access-date=29 December 2018}}</ref> An example was tested on the [[Stoner 63|Stoner 93]] in the early 1990s by the Royal Thai Armed Forces.<ref>The Small Arms review, Vol 13 No.1, October 2009</ref> In 1995, [[United States Special Operations Command]] selected the 4×32 TA01 as the official scope for the [[M4 carbine]] and purchased 12,000 units from Trijicon.<ref name="auto">{{cite web|url=https://www.trijicon.com/our-story/trijicon-history|title=Trijicon History|date=5 May 2021}}</ref> Between 2004 and 2005, the TA31RCO-A4 & M4 (AN/PVQ-31A & 31B) was selected as the official Rifle Combat Optic of the [[United States Marine Corps]], prompting Trijicon to produce 100,000 units for the US Marines in the following 18 months.<ref name="auto"/>

==Design==
[[File:USMC-08814.jpg|thumb|Down-range ACOG sight picture]]

The ACOG is available in a variety of configurations from the manufacturer with different [[reticle]]s, illumination, and other features. Most ACOGs do not use batteries for reticle illumination,<ref>thefirearmblog.com - Oct 2011, Trijicon came out with a conventional battery-powered illumination ACOG [http://www.thefirearmblog.com/blog/2011/10/28/trijicon-4x32-battery-acog/]</ref> being designed to use internal phosphor illumination provided by the radioactive decay of [[tritium]]. The [[tritium illumination]] has a usable life of 10 to 15 years.<ref>Tritium has a half-life of 12.5 years</ref> Some versions of the ACOG have an additional daytime reticle illumination via a passive external [[Optical fiber|fiber optic]] [[light tube|light pipe]]. Normally this allows the brightness of the reticle to match the field of view since it collects ambient light from around the sight, although this can lead to a mismatch in lighting — such as sunlight hitting the light pipe directly, or standing in a shadow — causing the reticle to be much brighter or darker than the target.<ref>{{cite web|url=http://jerkingthetrigger.com/blog/2010/03/16/tactical-handyman-acog-fiber-optic-fix/|title=Tactical Handyman – ACOG Fiber Optic Fix|date=16 March 2010}}</ref> Reticles have other features such as a [[Bullet drop compensation|bullet drop compensator]] and other different reticle shapes such as [[Chevron (insignia)|chevron]]s.

Some ACOG models incorporate rudimentary [[ghost ring]] [[iron sights]] as a backup for targets that are within {{convert|50|m|yd|abbr=on}}. Most ACOG models, when mounted to a carry handle, have an open space through the mount to allow the use of the rifle's iron sights without removing the scope.{{citation needed|date=July 2012}} Others include Docter<!--not a typo--> or Trijicon<ref>{{cite web |url=http://www.trijicon.com/user/parts/products1.cfm?PartID=699&back_row=6&categoryID=3 |title=TA648TRD: 6x48 Trijicon ACOG |publisher=Trijicon.com |access-date=2010-05-23 |archive-url=https://web.archive.org/web/20100103175639/http://trijicon.com/user/parts/products1.cfm?PartID=699&back_row=6&categoryID=3 |archive-date=2010-01-03 |url-status=dead }}</ref> [[reflex sight]]s mounted on top, such as the TA11SDO (SU-258/PVQ) and the TA648MGO (SU-260P).<ref>{{cite web |url=http://www.trijicon.com/user/parts/products1.cfm?PartID=531&back_row=4&categoryID=3 |title=TA01NSN-DOC: 4x32 Trijicon ACOG with 7.0 MOA Docter Optic |publisher=Trijicon.com |access-date=2010-05-23 |archive-url=https://web.archive.org/web/20100103174034/http://trijicon.com/user/parts/products1.cfm?PartID=531&back_row=4&categoryID=3 |archive-date=2010-01-03 |url-status=dead }}</ref> The ACOG ECOS line features both of these secondary sighting systems on the same scope.

Other features include [[Picatinny rail]]s like the TA648MGO,<ref>{{cite web |url=http://www.trijicon.com/user/parts/products1.cfm?PartID=609&back_row=6&categoryID=3 |title=TA648MGO: 6x48 Trijicon ACOG with Red Chevron Reticle and Accessory M1913 Rail |publisher=Trijicon.com |access-date=2010-05-23 |archive-url=https://web.archive.org/web/20100608012926/http://www.trijicon.com/user/parts/products1.cfm?PartID=609&back_row=6&categoryID=3 |archive-date=2010-06-08 |url-status=dead }}</ref> flip caps, and the ability to be [[waterproof]] up to {{convert|11|m|ft|abbr=on}}.<ref>{{cite web |url=http://www.trijicon.com/user/parts/products1.cfm?PartID=637&back_row=4&categoryID=3 |title=TA31RCO-M150CP: 4x32 Trijicon ACOG Army Rifle Combat Optic (RCO) |publisher=Trijicon.com |access-date=2010-05-23 |archive-url=https://web.archive.org/web/20100608012944/http://www.trijicon.com/user/parts/products1.cfm?PartID=637&back_row=4&categoryID=3 |archive-date=2010-06-08 |url-status=dead }}</ref>

Although the ACOG is designed for the Picatinny rail of the [[M16 rifle|M16A4]] and [[M4 carbine|M4]], it can be mounted on the carrying handles of previous models by using a special adapter.<ref>{{cite web|url=https://rdl.train.army.mil/soldierPortal/atia/adlsc/view/public/24979-1/FM/3-22.9/chap2.htm|archive-url=https://web.archive.org/web/20110720002648/https://rdl.train.army.mil/soldierPortal/atia/adlsc/view/public/24979-1/FM/3-22.9/chap2.htm|url-status=dead|archive-date=20 July 2011|title=FM 3-22.9 Chapter 2|date=20 July 2011}}</ref> 

==Bindon aiming concept==
Several ACOG models are designed to be used with the "''Bindon Aiming Concept''", an aiming technique developed by Trijicon founder and optical designer Glyn Bindon. The technique is essentially using the illuminated part of the reticle and its focusing rear [[eyepiece]] as a [[collimator sight]].<ref>Jane's international defense review: IDR., Volume 34, Issues 1-6</ref> As in any other collimator sight, the user does not actually look through the sight but instead keeps the collimated (infinity) image of the illuminated part of the reticle in focus with the dominant eye while the other eye views the entire [[field of view]] to acquire the target. In this both-eyes-open technique the brain superimposes the aiming reticle on the target. An added part of the technique is to shift focus after acquisition to the dominant eye/telescopic image for more accurate shooting. This overcomes the problem of centering or acquiring fast traversing targets common with all telescopic sights. Only certain models of the ACOG are designed with bright enough daylight-lit fiber optic or battery-powered LED reticles that facilitate this technique. 

==Controversy==
{{Main|Trijicon biblical verses controversy}}
[[Trijicon]] has been the subject of some criticism for inscribing references to [[Bible]] verses (e.g. [[John 8:12|JN8:12, referring to John 8:12]], "I am the [[Light of the World]]") alongside the model numbers on their ACOG sights. Starting in late 2009, Trijicon began shipping sights to the U.S. military without Bible verses.<ref>{{cite news |url=http://www.nydailynews.com/news/national/2010/01/19/2010-01-19_firm_takes_flak_for_rifle_scopes_with_bible_verse.html |title=Michigan Weapons Company Trijicon takes flak over soldiers' rifle scopes branded with Bible verses  |archive-url=https://web.archive.org/web/20190212081114/https://www.nydailynews.com/news/national/michigan-weapons-company-trijicon-takes-flak-soldiers-rifle-scopes-branded-bible-verses-article-1.458908|archive-date=12 February 2019|work=New York Daily News |date=2010-01-19}}</ref>

==Users==
*{{Flag|Finland}}: [[Finnish Defence Forces]]: 
**The TA11 is used by [[Finnish Army]] [[Jäger (infantry)|Jaeger]] platoons for [[designated marksman]] roles on [[RK 95 TP]] and modernized [[RK 62]] rifles
**The TA11 is used also by [[Finnish Navy]] [[Finnish Coastal Jaegers|coastal Jaeger]] units as a standard optic on [[RK 95 TP]] rifles
*{{flag|Georgia}}<ref>{{cite web|first=Miles|last=Vining|title=ISAF armament of BLS|date=22 April 2016|url=https://www.sadefensejournal.com/wp/?p=3523|access-date=14 September 2018|archive-url=https://web.archive.org/web/20180820203444/https://www.sadefensejournal.com/wp/?p=3523|archive-date=20 August 2018|url-status=dead}}</ref>
*{{flag|Indonesia}}: Used by Indonesian Army for standard Infantry Optic on [[Pindad SS2|Pindad SS2 rifles]].<ref>{{cite news |title=Spesifikasi Senapan Serbu SS2 Semua Versi Garapan Pindad, Ini Kecanggihannya! |url=https://www.kompas.com/tren/read/2022/01/27/203100965/spesifikasi-senapan-serbu-ss2-semua-versi-garapan-pindad-ini-kecanggihannya?page=all |access-date=30 June 2023}}</ref> also used by different units and branches.
*{{flag|Israel}}<ref name="Israel Defense Forces">{{cite news|url=https://www.ynet.co.il/articles/0,7340,L-3838264,00.html |title=ארה"ב: חברה תסיר פסוקים נוצריים מכוונות רובים |newspaper=Ynet |date=23 January 2010 }}</ref>
*{{flag|New Zealand}}: Used on [[Lewis Machine and Tool Company|MARS-L]] rifles.<ref>{{Cite web|title=Individual Weapons Replacement {{!}} Ministry of Defence Website|url=https://www.defence.govt.nz/what-we-do/delivering-defence-capability/defence-capability-projects/individual-weapons-replacement/|access-date=2021-02-02|website=www.defence.govt.nz}}</ref>
*{{flag|Spain}}: Used on [[Heckler & Koch MG4]].<ref name="Spanish Army">{{cite web|url=http://www.heckler-koch.de/HKWebNews/byItemID///22//3/15|title=Spanish Army procures the MG4 E|date=2007-08-02|publisher=Heckler & Koch|access-date=2009-05-02}}</ref>
*{{flag|United Kingdom}}: [[British Army]] and the [[Royal Marines]].<ref>{{cite web|url=http://www.army.mod.uk/linkedfiles/ceso/trained_soldiers/kit_magazine/kit62_hi_res.pdf |title=Kit Magazine, Issue 62 Winter 2007 |publisher=Ministry of Defence |access-date=2008-03-16 |quote=This technology is here now! So if you see strange-looking SA80s being carried by strange-looking men, then rest assured, those users that had the requirement, had the make-over, at a price. |url-status=dead |archive-url=https://web.archive.org/web/20081001234423/http://www.army.mod.uk/linkedfiles/ceso/trained_soldiers/kit_magazine/kit62_hi_res.pdf |archive-date=October 1, 2008 }}</ref>
*{{flag|United States}}: [[United States armed forces]] (see below), various law enforcement agencies.
**The [[United States Army]], [[United States Air Force|Air Force]] and [[United States Marine Corps|Marine Corps]] field the Trijicon TA31RCO ACOG, a 4× magnification model with a 32mm [[Objective (optics)#Telescopes|objective lens]] (4×32), with specially designed ballistic compensating reticles that are fiber optic & tritium illuminated, for the [[M4 carbine]] and [[M16A4|M16A4 rifle]].<ref>{{cite web|url=http://combatopticsreviews.com/trijicon-acog-ta31rco-m4cp/|title=Trijcon TA31RCO-M4CP Rifle Combat Optic Review - Combat Optics Reviews|website=combatopticsreviews.com}}</ref> This sight is designated the ''M150 Rifle Combat Optic'' in Army service and ''AN/PVQ-31 Rifle Combat Optic'' in the Marine Corps.<ref>{{cite web |url=http://www.trijicon.com/whats_new.cfm |title=Trijicon website |publisher=Trijicon.com |access-date=2010-05-23 |archive-url=https://web.archive.org/web/20100521053355/http://www.trijicon.com/Whats_new.cfm |archive-date=2010-05-21 |url-status=dead }}</ref><ref>{{cite web|url=http://www.pica.army.mil/picatinnypublic/news/archive/2008/12-19-08.asp |title=Picatinny hosts 2008 Type Classification and Materiel Release Awards Ceremony |publisher=Pica.army.mil |access-date=2010-05-23 |url-status=dead |archive-url=https://web.archive.org/web/20100401234102/http://www.pica.army.mil/PicatinnyPublic/news/archive/2008/12-19-08.asp |archive-date=2010-04-01 }}</ref> After an October 2005 evaluation, the USMC fielded 115,000 ACOGs so that every rifle and carbine in the Marine Corps inventory would be equipped with one.<ref name="Quantico.usmc.mil">{{cite web |url=http://www.quantico.usmc.mil/Sentry/StoryView.aspx?SID=63 |title=Quantico Sentry - Marines test combat optics curriculum |publisher=Quantico.usmc.mil |date=2005-10-27 |access-date=2010-05-23 |archive-url=https://web.archive.org/web/20110725012445/http://www.quantico.usmc.mil/Sentry/StoryView.aspx?SID=63 |archive-date=2011-07-25 |url-status=dead }}</ref>{{update after|2012|01|04}}
**The TA01NSN, a 4×32 ACOG with only tritium night illumination and backup [[iron sights]], is included in the [[SOPMOD|Special Operations Peculiar MODification ('''SOPMOD''')]] kit for the [[M4 carbine|M4A1 carbine]] used by [[United States special operations forces|Special Operations]] personnel to configure their weapons to individual preferences and mission requirements. Other Trijicon models have also seen service after being purchased at the unit and individual level.<ref name="Sweeney2012">{{cite book|last=Sweeney|first=Patrick|author-link=Patrick Sweeney (gunsmith)|title=Gun Digest Book of the AR-15|volume=IV|year=2012|publisher=F+W Media|location=Iola, WI|isbn=978-1-4402-2876-6|pages=232–233}}</ref>
** The Marine Corps field the Trijicon 3.5x35 SU-258/PVQ Squad Day Optic on the [[M27 Infantry Automatic Rifle|M27 assault rifle]].<ref name="review">[http://www.thefirearmblog.com/blog/2013/04/20/m27-impressions/ M27 First Impressions] {{Webarchive|url=https://web.archive.org/web/20130508132938/http://www.thefirearmblog.com/blog/2013/04/20/m27-impressions/ |date=2013-05-08 }} - Thefirearmblog.com, 20 April 2013</ref>

==Gallery==
<gallery mode="packed">
File:M4-Transparent.png|An [[M4 carbine]] with a TA01NSN ACOG
File:US Marine M16A4 Rifle ACOG.jpg|[[United States Marine Corps|USMC]]-spec M16A4 fitted with ACOG, vertical foregrip, and AN/PVQ-31
File:Saber Strike 2017 Norwegian STX Lane 170604-A-YI894-0138.jpg|Latvian soldiers using a [[Heckler & Koch G36]] rifle attached with Trijicon ACOG
File:24th MEU's Headquarters and Service Company conducts live-fire exercise 150310-M-WA276-018.jpg|TA648 6×48 Machine Gun Optic reticle
File:L129A1 Sharpshooter rifle MOD 45162218.jpg|A [[L129A1]] sharpshooter rifle with a TA648-308 6×48 ACOG fitted
File:Pindad SS2-V4 A1 dengan picatinny rail.jpg|An [[Pindad SS2|SS2]] equipped with ACOG
</gallery>

==See also==
* [[Sight (device)]]
* [[SUSAT]], British 4× telescopic sight with tritium-powered illumination similar to the ACOG
* [[Specter (Optic)|Specter]]

==References==
{{Reflist|30em}}

== External links ==
{{Commons category}}
* {{Official website}}
* [http://pewpewpew.work/sight/trijcon/ACOG.htm Japanese article with cross-section drawing of ACOG internal optical lay out]
* [https://patents.google.com/patent/US4806007A/en US patent 4806007A Optical gun sight]


[[Category:Firearm sights]]
[[Category:United States Army equipment]]
[[Category:Equipment of the United States Air Force]]
[[Category:United States Marine Corps equipment]]
[[Category:British Army equipment]]
[[Category:Military equipment introduced in the 1980s]]