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The History of the Legendary ACOG®


THE IDEA: 1986

Before it was the riflescope that changed everything, the Trijicon ACOG® was half a pair of binoculars. 

It was 1986. In the Detroit home of a Ford Motor Company aeronautical engineer, where binoculars lay wide open to show its eyepieces, prisms and objective lenses, Glyn Bindon looked intently at the product and had an idea that inspired the legendary ACOG. 

Glyn, who had worked on the Navy’s F-8U Crusader and also on projects for NASA during their pinnacle, wondered if moving the prism in a riflescope (similar to binoculars) could make it more compact than the big, bulky scopes on the market. He talked to optical experts and was told that moving the prism would be optically inelegant, potentially altering the light path and creating aberrations and a poor sight picture. 

In theory. 

He naturally ignored the naysayers and created a working, battery-free prototype with the help of a friend’s machine shop. He incorporated tritium to provide a red reticle at night and found a way to move the prism without lubrication inside the aluminum spherical seat in the external housing.  (This was another feature that was predicted to fail.)  

Glyn then created a minimalist design that simply followed the new light path.

Not only did the prototype lack significant optical aberrations, it was substantially lighter and more compact than anything on the market. 

But this engineer wasn’t finished. Glyn had previously worked on Department of Defense military contracts with Picatinny Arsenal, and he saw a unique opportunity.  A light, compact riflescope could benefit American troops. However, a light, compact, tough-as-nails riflescope could be a game-changer. 

Glyn named his concept the Advanced Combat Optical Gunsight (ACOG), and his goal was to strengthen it from the very beginning. He started with the same durable alloy as the M16 (7075 aluminum) and forged a housing that could withstand military drop tests, the harshest environmental extremes, and the rigors of military shock and vibration—all while using the lightest shell housing (with only a .047-inch wall at its thinnest point). 

Tough-as-nails, while extremely light and compact. In fact, many later called the ACOG “over-engineered.”

Before it was the riflescope that changed everything, the Trijicon ACOG® was half a pair of binoculars. 


From the very beginning, “follow the light” had dual purposes. Once Glyn discovered that changing the scope’s prism maintained an excellent sight picture and designing around the path of the light created a lighter, more compact design, he chose to celebrate his faith in God by adding a Bible verse reference on the original ACOG’s housing:  JN8:12

This refers to:  John 8:12 When Jesus spoke again to the people, he said, “I am the light of the world. Whoever follows me will never walk in darkness, but will have the light of life.”

The ACOG® 4x32 TA01 was introduced to the world in 1987.

The first models were not illuminated in the daytime like most current ACOGs. They featured black crosshairs for daytime and a tritium-illuminated red reticle at night. 

Contrary to popular belief, the ACOG did not immediately set the world on fire and Glyn did not quit his job at Ford. However, Glyn’s “side hobby” did move out of the Bindon house and into an official office in 1987.

During nights, weekends and holidays, Glyn, his son Stephen (currently president at Trijicon) and other family members continued to import OEG sights into America and also pursue other tritium technologies. In fact, Glyn obtained the first “exempt” license from the U.S. Nuclear Regulatory Commission for his pursuit of tritium-equipped iron sights. The company also sold a handful of ACOGs. 

At this time, Glyn found difficulty trademarking the name Armson, so he changed the company name to Trijicon (a combination of “tritium” and “icon,” with a “j” added to create three dots). The patent on the ACOG soon followed on February 21, 1989—the same year the company’s first big break occurred. 


In 1989, the U.S. Army investigated the replacement of the M16 and M4 rifles. Manufacturers from around the world competed for the contract, and three manufacturers chose the Trijicon ACOG 4x32 TA01 as their combat rifle optic of choice. (Word had slowly reached them of this “cool-looking” scope with amazing clarity and durability). 

During one of the tests, a manufacturer’s rifle blew up. The ACOG was still functional even though 2/3rds of the front lens had been blown off. This made quite the impression on the researchers. 

The U.S. Army did not choose a new rifle that year, but word of the ACOG’s success started to spread throughout the military. In fact, a handful of ACOGs were used in Operation Just Cause in Panama. 

ACOG® TA01 on the AAI Corporation Advance Combat Rifle Taken from DOD public archives gov.dod.dimoc.709024


The Trijicon ACOG was selling by the ones and tens. Then the big order came: 36. It was early 1991, and this was the most ACOGs sold in one military order, going to the U.S. military’s efforts in Operation Desert Storm.

The U.S. Navy SEALs also started to purchase the brand new 3.5x35 ACOGs for field testing that year. (These were small, but important, wins.) Between 1992 and 1995, the SEALs purchased several hundred more.


The new ACOG came with an updated feature: a red fiber optic illuminated aiming point which allowed the Bindon Aiming Concept to function.

This year, Trijicon also received a rare patent from Japan for the ACOG and continued to pursue patents around the world.



  • U.S. Patent 4,806,007
  • Canadian Patent 1,305,341
  • France Patent EP0315379
  • Great Britain Patent EP0315379
  • Japan Patent 2632976
  • South African Patent 88/8185
  • Swiss Patent EP0315379+NO
  • Austrian Patent EP0315379
  • Australian Patent 605 076


The curiosity of looking through an optic with “both eyes open” had gnawed at Glyn Bindon for years. He sold the popular Armson OEG product successfully since 1981, but because it depended on the relationship of the shooter’s two eyes, its zero could vary widely between two soldiers. This made it impractical for any military force. 

All magnified riflescopes on the market lacked the speed of target acquisition that was provided by keeping both eyes open. Glyn wondered if an illuminated red dot reticle would help the user acquire the target with both eyes open while keeping the reticle in the sight picture the entire time.

He discovered that with both eyes open, if there is a bright enough light in the reticle field when the weapon is being moved, the primary eye will see the illuminated reticle inside the sight, while the other eye sees the target and the background. These are two separate images, but the brain receives the signals from both eyes and automatically merges the images then automatically selects the magnified image received by the primary eye.

Because this was a discovery of how the brain works and is possible with any magnified scope with a bright enough reticle, it could not be patented. It was simply a discovery that Glyn made, and he named it the Bindon Aiming Concept, and became known in Trijicon circles as “BAC.”


In 1993, the ACOG 3.5x35 was officially adopted by German GSG9 SWAT on their SIG Sauer 550 rifles. It was also being thoroughly tested by U.S. Special Forces, as its illuminated reticles were becoming an ideal solution for close quarter battle (CQB) scenarios found in the Middle East.  

Trijicon continued to expand its ACOG line with the introduction of 1.5x16, 1.5x24, 2x20 and 3x24 models. 


U.S. Navy SEALs from SEAL Team 8 train with M4A1 carbines in Kuwait, 1998. DoD photo by JO2 Charles Neff, U.S. Navy

Based on the overwhelming success of the riflescope—both in testing and in theater—the U.S. Special Operations Command purchased 12,000 ACOG 4x32 scopes, choosing the TA01 as their official scope for M4 carbines.


This was the first official optic enhancement of the M16 family by the U.S. military.

And it was, by far, the largest ACOG order ever received at Trijicon. 

The ACOG’s prowess in the field grew steadily and it started to gain acceptance from military marksmen worldwide. In 1996 and 1997 the Israeli Special Forces purchased 5,000 ACOG 4x32 scopes for their designated marksmen.


Sales of the ACOG dropped back to lower levels after these two large purchases. Iron sights were still Trijicon’s number-one-selling product by a substantial margin, thanks to contracts with leading pistol manufacturers such as SIG Arms, Glock, Berretta and Smith & Wesson for their law enforcement customers.

In 2001, Trijicon introduced the 5.50x50 ACOG. And the 2.5x20 ACOG was adopted as the official optic of the British and Swedish armies’ new light antitank weapon, NLAW.  

In September of 2003, Glyn Bindon passed away unexpectedly and was not able to see his invention rocket to the top of the industry. 

In fact, Glyn and the Trijicon team had recently expanded their manufacturing footprint in their headquarters in Wixom, Michigan. But since the ACOG sales were not growing as fast as they had hoped, they were steps away from renting the new space out. 

A soldier is pictured aiming a practice NLAW with a Trijicon 2.5x20 ACOG® optic. United Kingdom MoD Photo | Image sourced from public domain


U.S. Marines zero their weapons systems U.S. Marine Corps photo by Lance Cpl. Dexter S. Saulisbury/Released

It took 18 years to produce and sell 100,000 ACOG 4x32 scopes, from 1987 to 2005. It then only took 18 months to create the next 100,000. 

The impetus behind this amazing growth was the adoption of the ACOG as the Official Rifle Combat Optic (RCO) of the U.S. Marine Corps. This was a multi-year contract that included a first delivery order of 104,000 ACOG 4x32 TA31 scopes. This model incorporated Trijicon’s exclusive dual-illuminated, red chevron-shaped reticle and bullet drop compensator. 

The Marines had, in fact, kept the ACOG on file for years after extensive, successful testing. However, the inflation of conflict in the Middle East created the immediate need for more rifle and riflescope support. 

“The ACOG mounted on the M16 service rifle has proven to be the biggest improvement in lethality for the Marine infantryman since the introduction of the M1 Garand in World War II.”

Major General J.N. Mattis
Commanding General, 1st Marine Division
Operation Iraqi Freedom


U.S. Army Staff Sgt. Kyle R. Petko uses his weapon's optic lens to scan the area while providing security during a patrol to clear routes in Khowst province, Afghanistan. U.S. Army photo by Sgt. Justin A. Moeller/Released

That new manufacturing facility space that Glyn planned to rent out? It was now humming with ACOG production. 

The U.S. Army chose the Trijicon ACOG 4x32 RCO as their field carry optic. The ACOG 3x30—featuring long eye relief, a BDC reticle and battery-free illumination was launched. At this same time, the U.S. Special Forces helped Trijicon create the ultimate combat optical sight. 

During the battles for freedom in Afghanistan and Iraq, a few U.S. Special Operations Forces began modifying their ACOGs by mounting a small red dot sight on the top. Word got back to the Trijicon team and the result was the creation of the 4x32 ACOG TA31 with a Docter Optic Red Dot Sight in 2006—the ultimate solution for both close-quarter battles (CQB) and long-range lethality. 

The next year, Trijicon released the ACOG 4x32 Enhanced Combat Optical Sight (ECOS). It was the first combat optic available to the public with the new Dark Earth Brown color required by special operations forces.


In 2008, Trijicon introduced its largest and smallest ACOGs to date. The ACOG 6x48 was created to handle the unique, heavy-duty needs of a .50 caliber weapon crew. And the 1.5x16 ACOG was a light, compact scope for fast-moving tactical operations in close quarters (which also become popular among speed-oriented competition shooters). 

In 2009, the 500,000th ACOG 4x32 scope was produced.

Trijicon also introduced green illuminated reticles for select ACOG configurations. 

The Trijicon RMR™ (Ruggedized Miniature Reflex) Sight was introduced in 2009 to replace the Docter Optic Red Dot Sight. The RMR featured a uniquely shaped housing for superior strength and offered two versions: an LED-illuminated reticle and a tritium/fiber optic-illuminated reticle. 

In 2010, the ACOG 1.5x16S (Short) TA44S-10 went on to win the NRA Golden Bullseye Award for “Optic of the Year.”

During this time, the ACOG success stories continued coming back from the battlefield. Law enforcement agencies across the world also began to take notice that the ACOG made an excellent scope for patrol rifles. 

The ACOG 6x48 was created to handle the unique, heavy-duty needs of a .50 caliber weapon crew. 


Trijicon expanded the ACOG line in 2012 with the addition of a battery-powered ACOG 4x32 LED. As the ACOG product grew in popularity, Trijicon responded to the need for customized colors and multiple ammunition-matching reticles. 


Trijicon expanded the ever-growing ACOG line with the introduction of the GEN2 Compact ACOG. The new ACOG retained the same legendary features as traditional models, while also offering easy-to-use, finer adjusters, watertight gaskets and a redesigned forged housing. Select GEN2 models featured a standard and low base height to better accommodate a variety of firearm platforms. 

That year, Trijicon also added a 3x24 model to the Compact ACOG line. This model offered a 24mm objective lens, 1.4 inches of eye relief and precise 1/2-inch click adjustments at 100 yards. The 3x24 ACOG featured popular Crosshair and Horseshoe Dot reticles, both calibrated for 5.56 and 7.62x39.



Trijicon is proud to announce the production of the 1,000,000th ACOG 4x32. More importantly, we’re proud to count as our customers the United States Marine Corps, United States Army, United States Navy, United States Air Force, United States Special Operations Forces, United States Government, state and local Law Enforcement and all of America’s allies. Not to mention the hundreds of thousands of civilian enthusiasts who trust the ACOG for their dedicated riflescope. 

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