#30 - Quiet Riot - Shoulder Launched Munitions
A Tactical Outlook by The Heavy Company & Vermilion
The US Army and US Marine Corps are moving out quietly and quickly on a significant revolution in infantry fighting equipment. The new programs cover service rifles, ammunition, suppressors, pistols, machine guns, sniper rifles, designated marksman rifles, and seemingly everything else the infantry carries. Frankly, this overhaul is long overdue. For just one example, the M16 family of rifles was adopted for service just short of 60 years ago. To give some perspective on that number, that would be like the US military entering WWII with the 1880 service rifle. That rifle would be the Springfield; not the familiar bolt-action version, but the even earlier Model 1873 Trapdoor Carbine.
With the pace of technological advance much quicker from 1964 to today than 1880 to 1940, this upgrade is long overdue. Vermilion and The Heavy Company are collaborating to provide our viewers with a deep dive into the new US shoulder launched munition (SLM) which will replace multiple Army and Marine Corps rocket systems. This developmental weapon has been christened the XM919.
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What is a SLM? We can thank a random Lieutenant from New Jersey, given a thankless task, who took inspiration from a trash pile for inventing the M1 Bazooka. Edward Uhl’s bazooka was the world’s first infantry rocket weapons system, fielded before both the German Panzerschreck and the Russian RPG-1.*
The bazooka solved a deadly problem facing American infantry forces. With WWII raging across the continents, it was clear that infantry units isolated from combined arms support were very vulnerable to armored forces. Additionally, WWII infantry forces still faced the same problems as their WWI-era fathers when attacking enemy infantry utilizing well dug-in defensive positions like trenches. Trench systems and other defenses still incorporated strong points. These points often housed powerful capabilities like machine guns, recoilless rifles, field guns, artillery spotters, or just larger concentrations of troops. Strongpoints then and today are reinforced by the construction of bunkers, pillboxes, block houses, and casemates. The preferred method for dealing with these strongpoints is blowing them up from afar.
Types of Modern SLM Rounds
The XM919 is designed to replace two general categories of infantry rockets and recoilless guns. The first category is designed to kill armored vehicles. These legacy systems (including the bazooka) employ a hollow shaped charge to detonate a metal liner within the warhead into a molten metal spike which penetrates the target vehicle's armor. In the present day, these warheads are commonly referred to as high-explosive anti-tank (HEAT) rounds.
HEAT Round in Operation
The second category of weapons replaced by the XM919 are those designed to kill the above-mentioned strongpoints. In these cases, the targets can be protected by thick layers of earth, sand bags, timber, reinforced concrete, triple brick walls, adobe, and/or cinder blocks.
For strongpoints, HEAT rounds could certainly inflict some damage but would be less than ideal. The hollow nose point is less likely to contact the inner layer of strongpoint construction, and more likely to contact an outer layer of sandbags or an earthen berm. This would fire the HEAT’s molten spike not against the targets inside but against a fortified outer layer of the strongpoint, minimizing damage to the target.
A simple solution to this dilemma is the high explosive dual purpose (HEDP) round. This is a HEAT round enclosed in a standard fragmentation casing. This way, if the HEAT’s molten spike is broken up or initiated early, the explosion still sends fragments bouncing around the impact zone, causing casualties.
HEDP rounds are also generally equipped with crush switches affixed to the round’s nose. These switches are able to differentiate between hard and soft impacts. If the crush switch detects a soft impact, this is almost certainly not the intended target but something like sand, earth, or strongpoint construction material. Soft impacts delay the fuze, allowing the round to burrow before detonation and maximizing the chance that the HEAT round functions properly. If the crush switch detects a hard impact, the fuze initiates immediately.
For attacking strongpoints, high explosive plastic (HEP) rounds can have superior effects on target compared to HEAT or HEDP. The round consists mainly of a plastic explosive which deforms and spreads on impact, covering a large surface area. Once the warhead deforms, the fuze detonates the explosives, sending a shockwave through the target. The shockwave causes pieces of the inner wall/armor of the target to break off into large fragments called spall, which bounce around inside the contained area causing casualties.
HEP Round in Operation
For HEP rounds, adding a high strength steel nose cone allows the round to burrow into the target before deformation, bypassing outer layers of defense.
A second type of more effective and advanced anti-strongpoint round is the anti-structure tandem (AST) round. In this configuration, the warhead has two phases of detonation that occur one after the other, or in tandem. A smaller HEAT warhead with a shallow hollow space is at the front of the round and creates a wide blast hole through the target. The second warhead (high explosive fragmentation) then continues through this hole and detonates inside the target.
A third type of even more effective anti-strongpoint round is the novel explosive (NE) developed by the US Marine Corps. NE is a thermobaric rocket meant to be fired against enclosed structures like buildings and bunkers. Once the rocket gets close or inside the target, a small explosive charge bursts the rocket open and sprays a fuel that mixes with oxygen to become a gas cloud, encompassing everything in the blast zone with billows of fuel-air mixture. A second explosive then ignites the fuel-air mixture, creating a fireball which sends shockwaves bouncing around the inside of the target. Personnel in the blast zone are severely burned while the shockwaves crush eardrums, lungs, and other internal organs.
As can be seen, the operation of HEAT, HEDP, HEP, AST, and NE rounds are all quite different. So it is quite ambitious for the US Army to combine anti-tank and anti-strongpoint capabilities into a single round. The XM919 is slated to replace the following systems:
M72 Light Anti-Armor Weapon (LAW): Norwegian rocket system firing a single HEAT round.
M136 Anti-Tank (AT) 4: Swedish recoilless gun system firing a single HEAT, HEDP, or AST round.
M136A1 AT4: Product improvement of M136 allowing the weapon to be fired from enclosed spaces.
M141 Bunker Defeat Munition (BDM): Norwegian rocket system firing a single HEDP round.
It is important to note that the XM919 will not be replacing dedicated heavy anti-tank missile weapons designed to defeat modern main battle tanks. These are systems like the FGM-148 Javelin and BGM-71 TOW, which are more sophisticated (being missiles) and more than twice the weight of the XM919 or the systems it is replacing.
Consequences for Strategic Competition:
The above weapons, despite upgrades, are based on ‘60s and ‘80s era technologies. A new light anti-tank solution is sorely required, and there are real benefits in developing a single multi-purpose light rocket. With a single rocket solution, the warfighter is not forced to pick which version to carry on patrol and avoids the risk of being caught by the enemy with the wrong rocket. A more lethal and efficient ground-fighting force is likely one of the most effective methods to deter China from attacking neighbors like Taiwan.
On the other hand, while the US moves out on equipping American infantry with significantly upgraded weapons, Washington is now leaving its allies in the dust. By developing exotic technologies (with possible export controls) and different weapons standards, US military logistics cannot supply the same warfighting material to allies as it does its own units.
Even during the height of surge combat operations in Iraq (2007-2008) and Afghanistan (2010), the Defense Department never seriously initiated developing standard issue weapons outside of NATO Standardization Agreement (STANAG) specifications like 5.56mm and 7.62mm small arms ammunition. For just one example, as the US Army fields new 6.8mm small arms, Japan just recently adopted the Howa 20 service rifle in 2019. While Japan is not a NATO member country, it employs most NATO STANAGs and the Howa 20 is chambered in NATO 5.56mm.
From Beijing’s perspective, the American unilateral infantry weapons upgrade program could signal many things. First, that the US is not just relying on allies like Japan, South Korea, Taiwan, and Australia, but is preparing to deploy its own infantry into the fight. Second, that the US military desires infantry overmatch against its declared pacing threat (China). Third, that the US is prioritizing American combat power over allied integration efforts, which could mean that the US believes it may have to “go it alone.”
Finally, the type of federal contract that the US Army will use to acquire the XM919 is greatly improved. In the past, acquisition of SLMs was done by specified lot sole-source order. This meant that when the Army or Marine Corps needed more rockets, it would request a specific number of units and then give the contract to a single company. For example, the Army might say it is purchasing 1,000 M136A1 AT4 weapons in 2024 and only SAAB Bofors Dynamics can produce this order.
This contract structure has led to increased costs (because there is no competition and the manufacturer can’t plan production over multiple years) and very minimal product improvement (because the single manufacturer has no incentive to innovate).
In the new approach, DoD will utilize multi-year open procurement contracts. This way, the Pentagons minimum munitions purchase will be known for many years (probably 5) so that defense companies are able to plan and sustain cost-efficient production. Additionally, the open nature of the contracts will allow many manufacturers to supply DoD, opening up the space for both cost and innovation competition.
Critically, the multi-year open procurement approach will hopefully keep the XM919 program agile enough to cut down per unit cost while responding to future threats such as the possible use of cross-laminated timber (CLT) in strongpoint construction. Per unit cost is especially important for rocket systems because high cost rockets can’t be widely used during training. Lower cost means more training shots and more proficient shooters.
* While the German faustpatrone (the predecessor to the panzerfaust) underwent field trials in 1942, it was not a rocket powered weapon (giving it much less range) and only went to full fielding in 1943.
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