USMC Fielding Squad Common Optic

Matthew Moss
by Matthew Moss
CWO4 Dave Tomlinson, infantry weapons officer at Marine Corps Systems Command, demonstrates the Squad Common Optic attached to the M27 Infantry Automatic Rifle, Feb. 10, aboard Marine Corps Base Quantico, Virginia. The SCO is an improved optic that improves target acquisition and probability of hit with infantry assault rifles. Marine Corps Systems Command began fielding the system to infantry and infantry-like units this year. (U.S. Marine Corps photo by Matt Gonzales)

The United States Marine Corps (USMC) has begun fielding a new standard magnified day optic for its small arms that will allow their infantry to engage adversaries at greater distances.

Designated the Squad Common Optic (SCO), the new scope can be fitted to both the M4 carbine series as well as the M27 Infantry Automatic Rifle and is a magnified day optic with an illuminated and non-illuminated reticle. The SCO will initially supplement and then replace the Rifle Combat Optic (RCO) and the Squad Day Optic currently in service with close combat Marines as the earlier optics wear out.

It is almost a year exactly since the USMC announced the selection of Trijicon’s 1-8×28 VCOG as the new Squad Common Optic. At the time Lt. Col. Tim Hough, MCSC’s Program Manager for Infantry Weapons, explained that “the Squad Common Optic provides greater lethality compared to the existing system, the Rifle Combat Optic”.

CWO4 Dave Tomlinson, infantry weapons officer at Marine Corps Systems Command, demonstrates the Squad Common Optic attached to the M27 Infantry Automatic Rifle on Feb. 10 at Marine Corps Base Quantico, (U.S. Marine Corps) Source:

Made by Trijicon, the SCO is larger and heavier than the RCO currently fitted to Marine M4s, weighing in at 31.5 ounces and 10.5 inches in length versus the 10-ounce, 6-inch RCO. However, it provides continuously adjustable magnification, providing the shooter from one-to-eight times magnification. This is double that of the current service rifle scope, which is fixed at four-power magnification.

Trijicon VCOG 1-828 (Trijicon)

Roger Boughton, MCSC’s lead engineer for the SCO program, explained that “having an optic that can reach out to longer distances will ultimately make the Marine a more lethal first-shot shooter.”

In a statement released by the SCO’s manufacturer Trijicon, Stephen Bindon, the company’s President & CEO said:

“Our warfighters deserve the very best equipment in defense of our nation. The Marine Corps’ SCO evaluation process was extremely rigorous, and we are honored that the VCOG was selected to continue the tradition of battle-proven riflescopes that the Trijicon ACOG began in 2004 as the Marine Corps’ first Rifle Combat Optic.”

The adjustable magnification allows the user much greater situational awareness, and this feature was widely praised by the testers who put the SCO through its paces before adoption, as was its durability.

Trijicon’s Global Vice-President of Sales & Marketing Chuck Wahr explained that:

“We introduced VCOG 1-8×28 to the commercial market in early 2019, but its design was inspired by requests from our warfighters. During design, development, and testing, we constantly challenged ourselves to produce a scope that would deliver the performance necessary in the most punishing of conditions.”

The scope is also described as agnostic when it comes to ammunition and weapon system, which allows for easy movement to a different host weapon. The SCO requires no tools to mount, being fixable to existing rails and accommodates the use of the M855 and M855A1 ammunition currently in service. Maj. Kyle Padilla, the Marine Corps System Command’s optics team lead, said that:

“It’s all about making an accurate decision. The SCO gives squad leaders or individual riflemen more time to make a decision to eliminate that threat if necessary.”

An initial order for 19,000 units has been placed at a value of $64 million. These are being issued to recon and infantry units initially, with complete fielding of the SCO expected by 2023. The adoption of the SCO once again demonstrates how seriously the USMC takes individual marksmanship.

This article was written by Ed Nash and originally published over on TFB’s sister site, Check out OVD for the latest defense news and updates.

Matthew Moss
Matthew Moss

Managing Editor: & Overt Matt is a British historian specialising in small arms development and military history. He has written several books and for a variety of publications in both the US and UK. Matt is also runs The Armourer's Bench, a video series on historically significant small arms. Here on TFB he covers product and current military small arms news. Reach Matt at:

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2 of 55 comments
  • Red dog Red dog on Mar 20, 2021

    I don't remember this being in tests with other sights and often wonder if the services don't confuse the most expensive as being the very best instead of this optic is the best in this price range thus the need for testing for the best in price and quality. I love my trijicon acogs. None better, and I enjoyed the many Marines that I worked with-most times. I was USN.

  • William William on Mar 21, 2021

    What happens with the old ACOGs?
    If they were sold as surplus to civs, I'd be down for one, but at the price they paid for them though, because as a taxpayer, I already paid for it once.