Laser-Guided Bullets? Meet America's Excalibur "S" Artillery Round

Marines with Charlie Battery, 1st Battalion, 12th Marine Regiment, fire an M982 Excalibur round from an M777 howitzer during a recent fire support mission. Afghanistan. 1 October 2011. U.S. Marine Corps.
July 9, 2020 Topic: Security Region: Americas Blog Brand: The Reboot Tags: ExcaliburLaser-GuidedU.S. ArmyArtilleryHowitzer

Laser-Guided Bullets? Meet America's Excalibur "S" Artillery Round

“Just because I can shoot farther, that does not mean I solve the issue. I have to acquire the right target. We want to be able to hit moving targets and targets obscured by uneven terrain.”


Key Point: It's a serious upgrade to the decade-plus old Excalibur.

Enemies hiding under a bridge, bunkered down on a specific floor in a large building, seeking cover on the back side of a mountain ridge or moving to attack in an armored vehicle convoy --- are all now more vulnerable to U.S. strikes due to an emerging laser-guided artillery round that can destroy enemy targets on the move in combat.


“We have many different experiments that are going on for long-range precision fires. We’re looking at new mobile firepower capabilities,” Army Vice Chief of Staff Gen. Joseph Martin told Warrior in an interview last Fall.

The laser-guided Raytheon-developed weapon is an upgrade or adaptation to the well-known, GPS-guided Excalibur 155mm round first fired in Iraq more than 10 years ago. Using GPS and Inertial measurement precision guidance technology, Excalibur can pinpoint and eliminate targets from 40km from current U.S. Howitzers -- within just two-meters of accuracy. The combat debut of Excalibur in Iraq ushered in what could be called a land-war transformation, marking the advent of a new kind of precision land attack.

Prior to precision-guided land artillery, 155m rounds were typically imprecise attack weapons used as area fire to blanket certain enemy areas, enabling forces to maneuver while under enemy fire. GPS-guided weapons from the air, such as Joint Direct Attack Munitions, had been in existence for well over a decade before Excalibur; Excalibur brought an at the time unprecedented measure of precision attack to land warfare.

While unprecedented at the time, the existing or legacy precision-guided Excalibur round can only pinpoint fixed targets; Now, Excalibur maker Raytheon has successfully demonstrated the ability for precision-guided Excalibur S rounds to track and destroy “moving” targets - using laser attack technology. The “S” round is engineered with what is called an enhanced shaped trajectory which, developers explain, enables it to make otherwise impossible adjustments in flight.

“This does give the round maneuverability to target a floor within a building, go under a bridge or hit the backside of a mountain,” Trevor Dunwell, Raytheon’s Excalibur Portfolio Director, told Warrior in an interview. “When you get to terminal engagement, the round can relocate depending upon target. This would be able to engage a moving convoy.”

The technology was recently used in a successful live-fire test at Yuma Proving Grounds, Ariz., wherein the Excalibur S round showed it could destroy targets on the move. Raytheon’s Excalibur S innovations are, according to developers, intended to align with the Pentagon’s modernization strategy and anticipate emerging requirements now being pursued for future warfare. The test, which fired the Excalibur S from a M777 Howitzer mobile artillery cannon, in collaboration with the U.S. Marine Corps, which is now analying data from the test firing.

The initial Excalibur rounds, including an upgraded 1B round, were developed for the Army, yet the success of the weapon has continued to inspire Raytheon and several military services to explore additional uses for Excalibur. In his discussion with Warrior, Martin cited the importance of advanced artillery weapons when it comes to precision fires and the Pentagon's increasingly vital cross-domain warfare strategy.

“We’re going to increase the capability of our cannons, we’re going to increase the capabilities of our artillery and rocket forces. We’re going to change the dynamics necessary to compete in the future on the multi-domain battlefield,” Martin told Warrior.

Dunwell explained that there have been some modifications to the weapon to accommodate laser designation, including seeker enhancements and various and laser-tracking sensors; using a laser designator or laser “spot,” targets can be “painted” by air assets such as drones or surveillance airplanes, or ground units. The laser spots give the round a specific target or point of attack to strike, while bringing an ability to keep a spot on a target as it moves. This is precisely what the Navy test was able to demonstrate.

Martin also referred to an emerging Army artillery weapon, also able to fire Excalibur, which promises to more than double the range of existing weapons and vastly alter the strategic and tactical landscape. The Army program, called Extended Range Cannon Artillery, has been developing for several years. During testing thus far, the Army has successfully fired a 155mm Excalibur round 60 kilometers - marking a technical breakthrough in the realm of land-based weapons and progressing toward its stated goal of being able to outrange and outgun Russian and Chinese weapons.This brings substantial implications regarding the Excalibur S, as it would greatly expand an ability to hit targets on the move from much larger ranges, using laser guidance.

ERCA is one of several current initiatives intended to address this challenge. Accordingly, the Army is now prototyping artillery weapons with a larger caliber tube and new grooves to hang weights for gravity adjustments to the weapon – which is a modified M777A2 mobile howitzer. The new ERCA weapon is designed to hit ranges greater than 70km, Army developers said. Currently, most land-fired artillery shot from an M777 Towed Howitzer or Self-Propelled Howitzer are able to pinpoint targets out to 30km - so hitting 62km dramatically changes Army offensive attack capability.​

Army senior leaders have been clear that the intent of the effort is to regain tactical overmatch against Russian and Chinese weapons. Citing the Russian invasion of Ukraine as a “wake-up call,” senior Army leaders consistently say that Russian weaponry, tactics and warfare integration are causing a particular concern.

Army senior leaders have consistently pointed to Russian land-war tactics in Ukraine as part of the inspirational basis for the U.S. Army’s current move to improve land-based firepower. The Army’s 2015 Combat Vehicle Modernization Strategy specifically cites concerns about Russia’s use of advanced weapons and armored vehicles in Ukraine.

“The Russians are using their most advanced tanks in the Ukraine, including the T-72B3, T-80, and T-90. All of these tanks have 125mm guns capable of firing a wide range of ammunition, including anti-tank/anti-helicopter missiles with a six-kilometer range, and advanced armor protection, including active protection on some models,” the strategy writes.

Raytheon weapons developers told Warrior that the 58 caliber self-propelled ERCA system is one of several current initiatives intended to address this challenge. For instance, the Army is also prototyping a Long Range Cannon (LRC), a modified version of its venerable M77A2 mobile howitzer. LRC will incorporate a 55 caliber gun tube, a Raytheon official explained.

The new ERCA and LRC weapons are designed to hit ranges greater than 70km, Army developers said. Currently, Excalibur shot from an M777 Towed Howitzer or M109A7 Palladin self-propelled howitzer are able to pinpoint targets out to 40km - so hitting 70km dramatically changes Army offensive attack capability.

“When you are talking about doubling the range you need a longer tube and a larger caliber. We will blend this munition with a howitzer and extend the range. We are upgrading the breach and metallurgy of the tube, changing the hydraulics to handle increased pressure and using a new ram jet projectile – kind of like a rocket,” a senior Army weapons developer told Warrior Maven in an interview.

Interestingly, metallurgical exploration and development was specifically cited by Martin as an area of modernization emphasis/

"We’re looking at leveraging the technology that’s available in the metallurgical development," Martin said.

The modification adds 1,000 pounds to the overall weight of the weapon and an additional six feet of cannon tube. The ERCA systems also uses a redesigned cab, new breech design and new “muzzle brake,” the official explained.

“The ERCA program develops not only the XM907 cannon but also products, such as the XM1113 rocket assisted projectile, the XM654 supercharge, an autoloader, and new fire control system,” an Army statement from last year said. The Army previously demonstrated a modified M777A2 Howitzer with an integration kit for the mass mock-up of the modified XM907 ERCA cannon at Yuma Proving Ground, Arizona.

ERCA, and the possibility of an Excalibur S, change the Army’s land war strategic calculus in a number of key respects, by advancing the Army’s number one modernization priority – long-range precision fires. This concept of operations is intended to enable mechanized attack forces and advancing infantry with an additional stand-off range or protective sphere with which to conduct operations. Longer range precision fire can hit enemy troop concentrations, supply lines and equipment essential to a coordinated attack, while allowing forces to stay farther back from incoming enemy fire.​

A 70-kilometer target range is, by any estimation, a substantial leap forward for artillery; when GPS guided precision 155mm artillery rounds, such as Excalibur, burst into land combat about ten years ago - its strike range was reported at roughly 30 kilometers. A self-propelled Howitzer able to hit 70-kilometers puts the weapon on par with some of the Army’s advanced land-based rockets - such as its precision-enabled Guided Multiple Launch Rocket System which also reaches 70-kilometers.

In a modern threat environment, wherein near-peer and smaller-level rivals increasingly possess precision-guided land weapons, longer-range C4ISR technology and drone weapons, increasing range is a ubiquitous emphasis across the Army and other services. Russia’s violations of the INF treaty, new S-500 air defenses, new Armata tanks and fast growing attack drone fleet - are all factors impacting Army decisions moving forward. In fact, senior Army developers specifically say that the ERCA program is, at least in part, designed to enable the Army to out-range rival Russian weapons.