Right now, I think that anti-armor weapons have gained an upper hand over tanks and other armored vehicles, and that the United States is falling behind in anti-anti-armor measures. They can take several courses to correct this. First, however, I want to lay out the history of the threat and how the current situation developed.
The First Tanks
Although it wasn’t the first battle in which tanks took part, the Battle of Cambrai in 1917 is the first major combined arms attack with a significant armored component, the use of armored vehicles beforehand having been relatively piecemeal. Together with the infantry of the 51st Highland Division, 476 British armored vehicles took part, of which 350 were combat vehicles (the rest were supply carriers and mobile radio stations, with perhaps some engineers in the mix). The attack succeeded, although as usual in the First World War the attackers proved unable to exploit their gains over the following days.
The British lost 179 armored vehicles, of which 65 were destroyed by enemy fire; crews abandoned the rest after getting stuck or breaking down. Over half of the destroyed tanks met their end near a small village called Flesquieres, more on that in a minute.
The principle combat tank at Cambrai was the Mark IV Tank, rather similar to the Mark VII seen in Indiana Jones and the Raiders of the Lost Ark. The Mark IV came in two major variants, a “female” variant armed only with machine guns and a “male” variant with not one but two gloriously phallic 6-pounder cannon, both types requiring whopping 8-man crew (including one man on each side of the transmission to shift gears). A 105 horsepower engine propelled the Mark IV’s 28-ton bulk, which not only kept its speed at a walking pace but severely limited its ability to negotiate terrain.
The Mark IV, and other WWI tanks, were armored against rifle fire and, as a result to some extent, nearby explosions. Anything heavier than a 30-caliber bullet came out of an artillery piece.
The Mark IV and its relatives, while it did provide some protection against artillery to its crew, seems to have still been relatively vulnerable to indirect fire. A direct hit, of course, would destroy it. I suspect that the protection afforded by these tanks’ armor to their crews was not substantially greater than the infantryman’s ability to lie prone — an especially effective tactic in the Great War, where the overwhelming majority of shells were impact-detonated, with the remainder relying on Victorian clockwork.
The most feared weapon, however, and the one which accounted for most of the enemy-fire casualties at Cambrai, was the field gun. These were smaller-caliber (at Cambrai, German 77mm guns; compare the French 75) artillery pieces that, given their relatively short ranges, were located further forward than heavier guns. Far enough, in fact, that in a pinch they could be moved all the way up, depressed and fired directly at attacking tanks.
The 77mm FK 96 nA, the most common German field gun of WW1
The thin armor of the early tanks did not require the use of special munitions to penetrate. The 77mm shells were simply fuzed to point-detonate, and were murder on the Mark IVs. These guns were not as mobile even as the cumbersome early tanks, and of course provided very little protection, having at most a gun shield.
The 77mm gun was slightly heavier than the 6-pounder guns mounted by the Mark IV, but its true advantages were concealment and low cost/high availability. Not only did the Mark IV suffer from truly primitive fire control and limited visibility, but crew communication was difficult and coordination poor both among and between crews. At Flesquieres, a reverse slope defense allowed the German defenders to exploit these disadvantages to the hilt.
Note several things about this engagement. First, there has never really been a Happy Time where armored vehicles preyed with impunity on the enemy. This is not true of aircraft. Early on, not only could early aircraft easily obtain game-changing information on the enemy, the experience of the Royal Flying Corps (e.g.) in the Middle East in strafing hapless desert warriors who had never faced death from above made a tremendous impression on flyers, as did the ability to simply fly over the enemy’s cities and hurl bombs.
Survivorship bias also enabled utopian thinking among flyers, but that’s another story.
Second, tanks don’t need to be invulnerable to be effective. Keep this in mind later; making antiarmor weapons “less effective” doesn’t mean making them completely useless, and by extension even the best of all possible worlds for the tanker doesn’t include his vehicle never being destroyed. Third, and related, armored fighting vehicles work as part of a combined-arms team.
The Interwar Period & Early World War 2
Armored combat never really came into its own during World War I, and aviation largely overshadowed armor in strategic thought. Nevertheless, the battlefield now unmistakably included armored vehicles of various classes: machine gun carriers, tanks, self-propelled artillery, assault guns, etc. Limitations on engine power meant that heavy vehicles could not move fast, and fast vehicles could not be heavily armored.
Armies developed three counters: obstacles, antitank rifles, and guns. Obstacles such as mines and antitank ditches were and continue to be highly effective, with the two drawbacks of immobility and double effect (you can’t drive over your own obstacles). The problem of antitank obstacles has changed little since WW2, and I don’t intend to talk much about them.
As mentioned above, the armor of early tanks protected only against rifle fire and shrapnel. A .303 will kill any of God’s creatures, therefore soldiers did not carry any firearm more powerful than a 30-caliber firearm, therefore the first tanks did not require more armor than needed to protect themselves.
The steel beast, however, is not a creature of God. Armies developed bigger rifles to hunt it. Initial experiments with overpressure .30-caliber rounds proving unsatisfactory, several European countries developed special high-power rifles. With the exception of the Polish Wz35, these all chambered rounds comparable to the .50BMG or a little larger, including the famous Lahti 20mm. Though generally ineffective at ranges over 300 meters, they were man-portable and, thus, both readily available and easy to conceal.
https://www.youtube.com/watch?v=tNQqLeE59s8
A training video for the .55 Boys Rifle
At the same time, the development of the heavy machine gun, driven more by war in the air than under armor, presented a similar threat. From what I can tell — with the major exception of the USSR — countries typically adopted one or the other. The US began a still-continuing love affair with the M2 Browning in 1921, but never issued an antitank rifle.
All serious countries, however, fielded antitank guns. No surprise, given the effectiveness of field pieces against early armor. Actually, the first change made to dedicated antitank guns was to reduce their power; the 75mm gun was overkill. At the outbreak of WW2, the typical antiarmor gun was a ~35mm cannon. Easier to manhandle than proper artillery pieces, these guns did require specialized operators. Despite being crew-served, deploying these guns did not (and does not — they’re still around) require the same level of coordination as indirect pieces. These guns fired both solid shot (for tanks) and explosive shells (for infantry).
The M3 37mm gun, a typical antitank weapon of early WW2
The use of solid shot meant decreasing penetration at distance. Heavier guns did sometimes use explosive shells against armored vehicles. A delay fuze allowed the round first to penetrate, then hopefully explode behind the armor, with devastating results. This method still suffered from decreasing penetration at range. Either way, antitank weapons generally did not outrange their prey, and in fact the power of antiarmor guns generally trailed tank guns throughout WW2. Cost/availability and concealment continued to be their primary advantages.
Putting an antitank gun on a vehicle created the tank destroyer. WW2 tank destroyers such as the M10 often resembled tanks themselves, but were very lightly armored and often slow to lay their guns, being deliberately made as cheaply as possible. Improvements in gunned tank destroyers led to their convergence with the Main Battle Tank post-WW2.
An M10 tank destroyer on display
Bringing the Heat
At some point during World War 2, both sides modified existing shaped demolition charges to create what is now known as a High Explosive Anti-Tank (HEAT) warhead. Even the first rudimentary HEAT warheads represented a significant improvement on existing weapons. Antitank rifles couldn’t penetrate more than an inch of steel armor, but by the end of the war, handheld antitank weapons could reliably destroy any tank, and they were not significantly more cumbersome than the rapidly superseded antitank rifles. Man-portable designs converged on shoulder-launched rockets. Cannon shells with HEAT warheads increased made low-pressure weapons like recoilless rifles vastly more dangerous to armor. Development of solid-shot antiarmor weapons continued, as the higher velocity and flatter trajectory of discarding-sabot rounds increased hit probability, but HEAT increasingly dominated.
A HEAT charge explodes
By about 1960, HEAT charges of about 80-90mm caliber could reliably destroy tanks from any angle. Tank armor still protected the crew against firearms (including heavy machine guns), and artillery, as well as lighter classes of AT weapons like the LAW (40-60mm range) from some angles. The French (AMX-30) and Germans (Leopard 1) simply gave up attempting to protect their tanks against direct hits, equipping the tanks mentioned above with only about 100mm of steel frontal armor.
Despite their power, infantry AT weapons had drawbacks of range and accuracy. The rocket had a warhead of fixed size; only so much propellant could fit without making the weapon too heavy to carry. The low velocity and density, along with a large lateral cross-section, made antitank rockets difficult to aim even with training — and operators tended to receive less training than tank crews. Again — low cost, high availability, and concealment. Towed antitank guns remained in use by Russia and its allies in the Warsaw Pact, but Western forces rarely used them; they used the same munitions as tank guns. The tanks of this era in some ways resembled the tracked and turreted “tank destroyers” of WW2 as much as anything else.
The AMX-30
Despite this apparent low point, tanks continued to be useful. They continued to provide mobile, protected firepower to ground forces. They also continued to be the best weapon to kill each other, especially in unrestricted terrain. Designs converged, situational awareness improved, and even rudimentary night-vision devices appeared. Again and again, superior training told in both armored and combined arms battles.
The Beginning of the Modern Era
Vietnam saw the first combat use of Anti-Tank Guided Missiles (ATGMs). The Soviets fielded the “Malyutka”, better known as the AT-3 “Sagger”. The Sagger consisted of a HEAT warhead mounted on a rocket. The operator watched the missile in flight through a sight, and maneuvered it onto the target using a joystick; the controller relayed correction data to the missile through a wire. This system, called Manual Command Line-of-Sight (MCLOS) required a great deal of skill, concentration, and usually bravery on the part of the operator. Despite having only about a 25% hit probability, the standard advantages of low cost, high availability, and ease of concealment made the Sagger extraordinarily lethal. However, they now had a new advantage: range. With a maximum range of three kilometers, the Sagger had a range at least equal to its targets. While the inherent difficulties of MCLOS guidance, the long time in flight, and other factors limited this advantage, it represented a serious new problem. ATGMs destroyed hundreds of Israeli armored vehicles in the Yom Kippur War.
The Americans skipped the development of MCLOS warheads with the BGM-71 TOW. Unlike the Sagger, the TOW missile contained a beacon on the back of the missile. The operator put the reticle of his command unit on the target, and the command unit tried to put the beacon on the reticle via data relayed (as with the Sagger) through wires leading up to the flying missile. This process, Semi-Active Command Line-of-Sight (SACLOS) is much easier to use than MCLOS. The TOW had a maximum range of nearly 4km, easily allowing standoff from tank cannon. Light vehicles equipped with ATGMs resurrected the tank destroyer concept.
The 5 Fingers of Death
The combination of range and SACLOS guidance made the TOW possible to fire from a helicopter (it’s not physically impossible to fire a baseline Sagger this way, but good luck getting a hit). Indeed helicopters scored the first TOW kills, in Vietnam. At about the same time, laser-guided air-to-surface missiles such as the AGM-65 Maverick allowed fixed-wing aircraft to reliably destroy armored vehicles on the ground (these were physically much larger than ground-launched ATGMs). Previously, aircraft attacking armored vehicles relied on dive bombing and strafing. Armored vehicles, especially tanks, were never much threatened by strafing (the GAU-8 was obsolete from Day 1 in this regard, by the way). Dive bombing did work, but with low accuracy and at the cost of significant exposure to ground fire.
AH-1 Cobra with TOW missiles (outside of the wing)
The Soviets quickly adopted SACLOS ATGM guidance, producing the AT-4 and AT-5 SACLOS missiles — the latter having virtually identical characteristics to the TOW– and retrofitting the AT-3.
So, as of about 1975, armor faced novel threats based on the standoff and precision afforded by Anti-Tank Guided Missiles. I’ll look a little more into the current threat, and what is being done about it elsewhere, in the next post.
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