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The history and development of the US Army’s Grenadier Sighting System is a remarkable story spanning many years, resulting in a sighting system that is unmatched for this type of small arm. In Part 1, we covered the US Army’s search for a new 40mm M320 GL in 2009. in brief, Contractors were afforded the opportunity to modify developmental GSS hardware at various points of the program plan based on written test results and Soldier feedback. The US Army was determined to ensure the program resulted in an effective GSS, which Soldiers wanted to carry and employ with their M320/M320A1 GL. The historical milestones are broken down as follows. In June 2015, the US Army issued its extensive GSS Request for Proposal. By August 2015, competitive offerers provided proposal responses and product samples. In April 2016, the US Army made two competitive awards with the intent of down-selecting a single production awardee. After three years of extensive development, testing, and evaluation in a competitive environment, the US Army chose the Wilcox GSS as the single production awardee in June 2019.

Soldier user feedback was included in the various Army test reports. Excerpts from the final US Army developmental test reports included these statements and comments specific to the Wilcox GSS:

“Favored use of the GSS with M320/320A1 GL”

“GSS Enhances our Mission”

“The GSS was very accurate, even perfect”

– Operational testing responses

It’s important to reference the stated operational testing evaluation criteria placed a high emphasis and focus on 1) Soldier in the loop Accuracy, 2) Speed of Engagement Time, and 3) Soldier Acceptance (based on usability, suitability, effectiveness, and human-system interface design).

The US Army’s Test report from 2019 highlights the enhanced accuracy and hit probability of the GSS. The Wilcox GSS enhances both soldier lethality and survivability. Also, GSS provides substantial ammunition cost savings through its proven Soldier-in-the-loop target hit rate. On the M320 standalone the hit rate of the GSS is 52% as compared to 25% for the standard M320 leaf sight. The Wilcox GSS produces more than twice (2X) as many hits for a given grenadier load. In the case of the M320 GL underslung (M320 with M4), the Wilcox GSS has a hit rate of 58% as compared to 17% for the M320 leaf sight. In this case, the Wilcox GSS produces more than three times (3X) as many hits for a given grenadier load.

The US Army’s comprehensive plan succeeded in developing and selecting a highly effective day/night sighting solution for the M320/M320A1 GL. Simultaneously, the Wilcox GSS is forward upgradeable by design. It allows the unit to download ammunition ballistic data tables for new 40mm rounds. This inherent design supports the entire weapon, ammunition, and sighting system (GSS) to remain relevant for years to come to further support the customer’s investment. The Wilcox GSS, under contract with the US Army, is the sight of choice for all new ammunition under US Army development, specific to the M320/M320A1. The US Army spent years of careful planning, applying lessons learned, developing, testing, and executing the GSS program production selection.

WILCOX GSS ENTERS PRODUCTION UNDER US ARMY CONTRACT

At its US-based facility in Newington, NH, Wilcox conducted exhaustive First Article Testing (FAT) with Government oversight. Subsequently, the company entered and maintains full-scale production of this highly effective day/ night sighting system for the M320/320A1 GL. At present, Wilcox is delivering monthly production to support US Army Fielding. The Wilcox facility comprises 220,000 square feet of design, development, and production space. The company is highly vertically integrated which translates into making many of its own components. The company is prospering and plans an additional 80,000 sq. ft. expansion.

WILCOX GSS DISCRIMINATING DIFFERENCES

Up to this point, most manufacturers had taken the easy route by bolting on a day sight atop a laser module to provide a hybrid product. Although such a systems approach was easier for manufacturers, it was full of compromises, such as multiple batteries/compartments and separate windage & elevation settings for day sight and lasers, etc. Wilcox engineers set out to make an integrated day/night sighting system. A solution designed, manufactured, and tested with the user in mind. This required a fresh approach, full of first-of-its-kind disruptive technology, as well as, new system design and manufacturing approaches.

Wilcox seized upon years of prior work in the field with its associated expertise and the opportunity to listen to the voice of customer inputs. The US Army provided comprehensive Developmental Test Reports, which included Soldier operational test results with added comments. Wilcox engineers sifted through these reports to extract important indicators, preferences, and associated test results. These Developmental Test Reports were supplied to both initial Development contract awardees for their own respective GSS, after Development Phases I and II.

As previously indicated, the operational testing evaluation criteria during the Development phases placed a high emphasis and focus on these critical criteria: 1) Soldier-in- the-loop Accuracy, 2) Speed of Engagement Time, and 3) Soldier Acceptance. It was on these important care-abouts, that the Wilcox GSS excelled. The US Army’s Request for Proposal (RFP) defined Soldier Acceptance as usability, suitability, effectiveness, and human-system interface design.

Here are a few examples of Wilcox system design that led to broader user acceptance. Based on an innovative optical bench, there is one windage and elevation adjustment for the day sight with backup iron sight and all lasers. This resulted in a system with ease of use and training as a feature, which ultimately benefited the user. Although it was not required, the inclusion of a visible day laser, in addition to the near-infrared (NIR) laser pointer and NIR illumination made the Wilcox GSS easier to boresight at any time, with or without night vision device(s). Combine the single optical bench approach described above for both the day sight with backup iron sight and lasers, the ease of use just multiplied exponentially. Other day/night sights are designed to require first boresighting the day sight and separately boresighting the near-infrared lasers while using a night vision device. Wilcox engineers designed and built the GSS to have increased usability.

The day optic for the Wilcox GSS contained some unique features including expanded reticle capabilities.

• Choice of 1 of 4 Selectable Reticles as shown

• Adjustable Reticle Brightness

• Quick Range Estimation, Circle full reticle designed for man-sized at 200 meters
• Unique Cant Indication to reticle allows Grenadier to maintain eyes on the target

Given the M320 GL ammunition has a much lower muzzle velocity than traditional pistol/rifle ammunition, the accuracy of the round is more susceptible to cant. The GSS is equipped with a cant indicator, which provides operational feedback. The Wilcox GSS has a truly unique method of illustrating cant that allows the grenadier to maintain eyes downrange on target with complete situational awareness. Other day/ night sights have a separate display indicator requiring the grenadier to break eye contact with the target downrange and look at a display on the rear of their day/night system. This method loses valuable time of engagement and requires the reacquisition of the sight picture and target. It is not practical, yet this is the cant indication methodology chosen by most other grenade day/night sights. The Wilcox GSS has the cant indicator integrated in both the day and night sighting systems.

For the day sight the aiming Reticle signals to the grenadier any excessive cant angle when preparing to fire.

During the day, the grenadier never has to break the line of sight with the target and be forced to reacquire/sight the target. This provides a significant tactical advantage while preserving precious time and situational awareness.

At night, the NIR aiming laser will blink if the weapon is canted and return to a steady continuous laser when in the proper position. During the night, the grenadier never has to break line of sight with the target while viewing through night vision goggles, to peak at a rear display on the system, to be aware of cant position. Again, this provides a significant tactical advantage, while preserving precious time and situational awareness for nighttime engagements.

The Wilcox GSS NIR Illuminator uses the latest Vertical Cavity Surface Emitting Laser (VCSEL) technology, which produces a clean uniform beam without artifacts, as seen in typical traditional weapon-mounted NIR illuminators. The integrated VCSEL technology helps to increase night vision goggle (NVG) recognition and identification ranges for traditional green phosphor and modern-day white phosphor image intensification tube assembly for NVGs. Another Wilcox GSS discriminating difference to support users.

The Wilcox GSS incorporates “On the Fly” power adjustments to increase/decrease reticle brightness and laser power intensity. When in the Red Dot “RD”, day optic mode, these two buttons allow the user to easily increase/ decrease reticle brightness. While the Wilcox GSS has an onboard light sensing system and can automatically set reticle brightness, users desired a quick manual method to change the brightness, if desired. For lasers, the Wilcox GSS has High and Low power settings with a mechanical blue lockout allen screw, a common mechanical visible safety for weapon-mounted laser mode switch. In addition, when the Wilcox GSS is set to one of the multiple laser modes, the same two triangular-shaped buttons shown allow the user to increase/decrease the laser power intensity within either the Dual High “DH” or standard low power mode settings for the Aiming Laser “AL” or Dual Laser “DL”. This provides users the capability to easily optimize the laser power settings to match environmental conditions more closely. For example, in a conventional competitor’s offering, if the High- power laser(s) are too bright and start to bloom or wash out surrounding objects, their option would be to revert to the Low Power setting; this may or may not be adequate for a given nighttime viewing condition. With the Wilcox GSS, the user can use the two buttons to decrease/increase within the High-power “DH” mode to optimize for NIR viewing within the NVG.

In summary, the Wilcox GSS is a compact and lightweight day/night sighting system selected after years of exhaustive and extensive testing. It is powered by a single integrated AA battery, which is widely available worldwide. It provides reduced Size, Weight, and Power (SWaP). Further, the GSS is the sight of choice to work with the US Army’s conventional ammunition as well as the XM1166 High Explosive Air Burst (HEAB) round of 40mm ammunition under development by the US Army. In addition to having discriminating feature advantages over others, it is designed with forward Capability and Compatibility in mind.

“The Wilcox GSS day/night sight is a tribute to the innovative approaches of its program management, engineering and quality team members. The Wilcox team leveraged Army report feedback and worked collaboratively with US Army program team to develop an effective and reliable day/night sighting system for use on the grenade launcher.”

– Jim Teetzel,
Wilcox CEO & Founder

The history of the US Army’s Grenadier Sighting System (GSS) is a remarkable story that exemplifies a successful program collaboration between the US Army and the Wilcox Special Projects Team. The Wilcox Grenadier Sighting System day/night sighting system for the M320/M320A1 grenade launcher is the result of over a decade of design refinement, development, testing, continuous improvement, and ongoing production in conjunction with the US Army; it is simply the most accurate, user-friendly, forward-upgradeable day/night sight for the M320/M320A1 GL in the world.

Learn more about the Development of the Wilcox Grenadier Sighting System or download the GSS Case Study.