Megacities, Musketry, Physics and Why the Intermediate Cartridge Needs to Disappear
“Megacity” is not a term in the general lexicon of most people. It is typically defined as any metropolitan area with a population of 10million or more. It is often that eyes simply glaze over when reading dry figures, though, so some perspective is useful, for the purposes of scale.
The three largest megacities on Earth, as of this writing (April 29, 2022), are Tokyo, Japan; Delhi, India; and Shanghai, China:
- Tokyo currently has a population in excess of 37,000,000 – or, approximately the same population as the state of California
- Delhi is currently in excess of 29,000,000, roughly equal to the entire population of the state of Texas
- Shanghai comes in third, with over 26,000,000 people
Those three cities easily fall within the category of the “First World” – comparatively wealthy and reasonably peaceful. However, there are other megacities that do not fall into this category:
- *Karachi, Pakistan, with nearly 17,800,000
- *Mexico City, with over 22,000,000 people
- *Brazil’s Rio de Janiero, comparatively small with “only” c.13million
This second group of megacities are in extremely unstable environments. Indeed, the issue of civil crime control in Rio is an ongoing nightmare, frequently compared to low-intensity military conflict. As a result, the US Military’s Special Operations community is justifiably concerned that it will find itself operating in such an environment in very near future.
It also knows that it is not ready to do so:
Megacities Urban Future, the Emerging Complexity, Pentagon Video
Unlike certain shrill commentaries, one of the fundamental facts of military operations in the Twenty-First Century is that winning the population is far more important than winning arbitrary physical space. As of this writing, fully half the world’s populations can be considered to live in urban environments. That figure is expected to increase to c.65% by 2050 – less than thirty years away – with an estimated 90% of that growth being concentrated in Africa and Asia…and fully half of those populations will be of “fighting age” (not in the conventional, legal terminology, but in terms of reality), between 14 and 30.
Operations in large urban areas are complicated by the very infrastructure that make those cities possible: the US military had serious issues operating against insurgents in Baghdad (with a comparatively small population of c.8million) because the city was so large, it was nearly impossible to control vehicular movements to protect civilians, much less impede guerrilla’s. Likewise, even fighting in a moderately large city, such as Grozny, reveals the dangers of engaging in high-intensity operations, even when civilians are treated as an afterthought.
This is not simply a “4th Gen” problem. There are many reasons short of active, intentional conflict that could cause a military force to deploy into a megacity. From natural disasters, to criminal activity, to pan-national, extra-national and post-national activity, military forces around the world cannot avoid megacities, nor the concerns that accompany them.
But — what does this have to do with cartridges and physics?
Simply put, armies are going to have to fight in megacities. This is an absolute: whether the battle begins tomorrow, or five years from now, it will happen. Some group or groups will force a real infantry battle inside a megacity.
And the militaries of the 2020’s and beyond are neither equipped nor trained to deal with it – the US military is right to be concerned. However, in trying to identify concerns, in order to address them, the US military has a serious blind spot that they do not want to address, a proverbial “Emperor with no clothes“…That problem, seemingly easy to fix, is a fundamental question of small arms.
Since the end of the 1960’s, the US military has been fixated on the intermediate caliber class of rifle. For completely different – and frankly, rather shabby – reasons than the Soviet Union‘s adoption of an intermediate caliber, the US military has used the 5.56x45mm round for both its primary infantry combat weapon, as well as its Squad Automatic Weapon (SAW) since the early-to-mid 1960’s. Pundits who should know better, take the fact that the 5.56×45 cartridge has been deployed in combat by the US for around fifty years as a sign that it must be superior.
So — what’s the problem?
Based in part on data from the URBAN WARRIOR exercise series – conducted prior to 9-11 – the US Marine Corps’ Warfighting Laboratory constructed an outdoor laboratory to test the effects of various cartridges against commonly-encountered structural environments. The results are telling:
Urban environments are…well, “urban”: they are constructed of a variety of materials of changing density, offering considerable opportunities for concealment (i.e., materials that a person can hide behind, to avoid observation), but a wide array of material densities make for rapidly changing levels of “cover” (a barrier that offers some level of protection against various kinds of projectiles). Many of these materials are proof against lighter projectiles.
The modern M16/M4 rifle and M249 SAW projectiles are 62 grains in weight. Even the most aggressive load commonly issued, the SS109, tops out at 3,100 feet per second (fps) in velocity. This delievers about 1,300 foot-lbs of energy onto a target.
In contrast, the 7.62x51mm M80 round used by the standard medium machine gun, the M240, weighs in at 147 grains, and comes out of the barrel at about 2,700fps, while delivering almost twice the energy in foot-lbs (c.2,400). Obviously, not every soldier can run around with a comparatively heavy machine gun…however, the 7.62x51mm round was – and is – used by rifles.
Although now used almost exclusively by dedicated snipers, the round was used not only by the M14, with the M16-series replaced, but was the standard rifle cartridge of NATO forces for nearly thirty years. While these rifles were and are demonstrably heavier and longer than their smaller rivals, the need to batter through effective cover is a consideration that becomes increasingly important in an urban environment.
This is not a case of technical nitpicking — using lighter projectiles in an urban environment means that more rounds need to be fired to overcome barricades. And, when the only firearms that can effectively batter through such materials are fired by weapons that used to be considered a form of light artillery, it should be obvious that this is not conducive to a positive image before the ever-present, all-seeing eyes of news cameras and the ubiquitous camera-phone.
While it would be understandable if this were a simple case of “Oops! We got it wrong!“, this is not the case, as instructors at West Point, the primary officer academy of the US Army, were teaching this in the early 1980’s:
Nor is this a question of engagement ranges. The original work that created the intermediate cartridge, begun in the spring of 1918 with a report from Hauptmann (Captain) Piderit, part of the “Gewehrprüfungskommission (Small Arms Proofing Committee)” of the German General Staff in Berlin, was based on the flawed logic that since infantry combat ranges were usually well under 800m, a smaller, lighter projectile would save on materials and costs, as well as allowing for significant improvements to rifles.
While this might have been true on its face, it ignored the consideration of cover. The result has been rifles that perform well enough on rifle ranges and in open environments (although some would disagree), but are far less effective in built-up areas…which is precisely where they are about to find themselves, to say nothing of longer ranges.
The US Army “solution” to the problem was announced on April 19, 2022 – the Army’s (and thus, the US military’s) new weapon would be….the SIG Sauer XM5 Rifle, a derivative of the company’s “MCX SPEAR“, and its associated light machine gun, the XM250. (Certainly a feather for SIG’s plume, considering the US military already having bought their handguns.)
Technical Review Sig Sauer Next Generation Squad Weapon NGSW-R XM5 rifle NGSW-AR XM250 machine gun
While the XM250 is, indeed, lighter than what it replacing – the M249 SAW – the XM5 is heavier than the M4 carbine it replaces. The discrepancy in rifle weights is odd, until it is realized that the 6.8x51mm “SIG FURY” round has a chamber pressure – in normal loads – of c.80,000psi, a staggering figure fully 25% higher than that of the venerable 7.62x51mm M80 cartridge, and a minimum 35% higher than the original 5.56x45mm M198 used by the M-16; it is even more than 30% higher than that generated by a .50BMG Saboted Light Armor Penetrator round. This is not “fun with numbers“: when you start dealing with this level of pressures, the measures to contain them are critical…and heavy, in the extreme. One seriously wonders if the US Army is planning on fighting flying saucers.
While “newer” is often seen as “better”, this is far more than necessary. While poorly-made barrels will certainly burst, increasing the pressure by c.30%, minimum, is dangerous enough to be irresponsible. Weapons using the older 7.62x51mm M80, while no lightweights, were more than sufficient for a broad range of combat tasks. Lighter weapons, firing lighter cartridges, simply had less range, poorer performance, and less utility…and, speaking from experience, the rifles weren’t all that light.
Physics do not lie, and the lighter rifles were not that much lighter.
Given the myriad additional problems inherent to “FIBUA” (“Fighting In Built-Up Areas”, the old term for MOUT/”Military Operations in Urban Terrain”), steps need to be taken by Western militaries to adopt a more effective cartridge.
The question is, will they do so, before a disaster happens in front of worldwide nightly news?
