Period: Fill & Download for Free

No, it was never official doctrine or actual practice for US tanks to leave the job of fighting enemy tanks entirely to US tank destroyers.US tank destroyers and the doctrine behind them are commonly misunderstood. US tank destroyers got the really big anti-tank guns, while US medium tanks got somewhat anaemic guns, unlike those hulking late war German tanks.Tanks are supposed to fight tanks, weren't they? Yes, but in US doctrine, tanks were also supposed to fight infantry, take out anti-tank guns, destroy artillery and help out the infantry by blowing up field fortifications like bunkers and trenches.If you want doctrinal chapter and verse, here's what the US Army said medium tanks should do:(3) Medium tanks.-(a) The primary mission of medium tank units is to assist the attack of the light tank units, chiefly by neutralizing or destroying the hostile antitank weapons. When organized resistance is encountered, especially antitank guns, medium tank units will usually precede the light tank units for this purpose. The use of one or more platoons of medium tanks following the attack of light tank units for supporting fire will frequently be desirable. Tanks so employed, for short periods, should assume turret defilade positions from which they can bring direct fire to bear on hostile antitank weapons as they are found.(b) Medium tanks also protect the light tanks against the attack of hostile tanks. When the enemy is composed of mechanized troops, a large medium tank component, if available, is held in the reserve.Note that the job of US medium tanks wasn't primarily to fight enemy tanks.And here's what tank destroyers were supposed to do:(2) Missions.-(a) The mission of the tank destroyer with the armored division is to assist either by offensive or defensive action in the protection of the division against hostile mechanized forces.(b) The battalion may be used to-1. Protect a bivouac, assembly area, or rallying point.2. Guard an exposed flank.3. Protect the rear of the division.(c) The battalion may be used as a unit or companies may be attached to armored regiments or combat commands. Except when actually emplaced to protect a bivouac, assembly area, or rallying point, tank destroyer units should be held in mobile reserve, prepared to move promptly to any threatened area.(From FM 17-10, ARMORED FORCE FIELD MANUAL: TACTICS AND TECHNIQUE, http://www.ibiblio.org/hyperwar/USA/ref/FM/PDFs/FM17-10.PDF)This was US Army doctrine in 1942. Tank destroyers were an innovation then.The idea of tank destroyers arose from US observations of the defeat of France. One conclusion the US Army drew was that anti-tank guns did pretty well in knocking out tanks, but were vulnerable to being flanked or bypassed and could not be easily withdrawn. But if the anti-tanks guns had trucks or half-tracks to tow them away, they would be much less vulnerable and could be moved to where the tanks were. An even better solution would be to mount those anti-tank guns on trucks or half-tracks in the first place, and better yet, mount them on a tank chassis for even more mobility. Thus the tank destroyer was born.But tank destroyers were not an integral part of a US armored division or a US infantry division. Tank destroyers were organized as independent battalions, parcelled out to US armored or infantry divisions to beef up their offensive or defensive power for a particular mission and not on a permanent basis.So tank destroyers didn't always operate with tanks and it just would not have made sense for doctrine or practice to prescribe that US tanks to withdraw and let the tank destroyers deal with enemy tanks, not least because making an orderly withdraw in the face of the enemy is difficult.The 1942 prescription for an attack was:g. Tactical groupings.-In attack the combat command groups generally are disposed into four parts: a reconnaissance force (consisting of organic reconnaissance units and attack units), a striking force (the striking echelon consisting of tanks with engineers attached), a supporting force (consisting of the support echelon, i. e., the infantry, artillery, and tank destroyer units), and a reserve. Whether the striking force makes the initial attack or main attack will depend on the terrain and the extent and dispositions of the hostile antitank defenses.(1) Striking force.--When terrain is favorable for tank operation and hostile antitank defenses are not strong, the striking echelon supported by available combat aviation makes the initial attack. This attack is usually by envelopment, the supporting echelon being used as a holding force or base of fire, or a portion of the tank units may be used for such holding or secondary attack. The striking echelon will make the initial attack in a penetration only when hostile defenses are very weak or when given overwhelming air and artillery support. Engineers are usually attached to the striking echelon. Infantry may be attached.(2) Support force.--When the striking force makes the initial attack, the support echelon follows to seize and hold objectives taken by the striking echelon. When terrain is un- favorable for tank operation or antitank defenses are strong, the support echelon, supported by medium tank units, may lead the attack to secure ground from which the striking echelon may attack. The support echelon usually leads the attack in a penetration. The support echelon may be used to make an attack initially to serve as a base of fire for the striking force in an envelopment. This attack serves to fix the enemy and may attract his reserves. In this manner it assists the advance of the enveloping or striking force.In the attack, tank destroyers - if they were present - were to fix the enemy in place so the tanks in the striking force could maneuver to flank or encircle the enemy.That was the theory in 1942, but by 1944 tactics had changed. The US Army realized the value of "combined arms" - a mixture of tanks, infantry and artillery working together - but there were organizational obstacles to this: infantry and tanks were grouped into separate battalions in US armored divisions and often did not get practice working together. The US Army tried to reorganize divisions around "regimental command teams" composed of tanks, infantry, artillery, engineers and other supporting units semi-permanently but the tank destroyer battalions were not permanently attached to divisions and were not a regular fixture of regimental combat teams.By 1944, tank destroyer battalions were being attached for long periods to infantry divisions, long enough for infantry and tank destroyer units to work out combined arms tactics, more so than attached tank units. And the tank destroyers were useful to have around to act as assault guns blasting bunkers and strong points in infantry attacks.One last comment, regarding the assertion that "so many tanks were lost." Judging tank losses in any given battle is really hard. A division might lose most of its tanks in a pitched battle and within a day or two be back to its original strength. Some the tanks might be replaced from reserves, but many tanks were repaired and returned to their units in a day or two. Rough rules of thumb during the campaign in Europe were: about 40% - 50% of Allied tanks were repaired within 24 hours, maybe another 25% - 30% were repaired within a couple of days to a week and around 10% - 20% were total write-offs.

On the tank side of the house, the myth that US doctrine held that tanks were not supposed to fight tanks but that was the sole purview of the Tank Destroyer force, or that the tank destroyers as the US used were a unique concept to the US is utterly pervasive. It doesn’t make me roll my eyes, which implies that the misconception is a ‘daft’ one, as it has become so entrenched that I normally have to end up citing anything from field manuals to vehicle development history in order to even get people to question their belief on the matter.In reality, there was no such concept in doctrine, medium tanks were supposed to engage anything they met. They were equipped with the best gun that met requirements that could be put into them at the time, varying from the 37mm in the M2 medium to the 75mm when M4 came out. (People seem to forget, for some reason, that when Sherman entered production, the US tank destroyers were being built with 37mm (M6 GMC) and 75mm (M3 GMC) guns. The upgraded M4 came with the same 76mm as the ‘ideal’ tank destroyer, the M18.Tank destroyers as implemented by McNair and Bruce were a purely defensive concept, were not to be used in the attack (leaving enemy tanks to US medium tanks) and the general design specifications of light weight, open top, and mobility to respond to breakthroughs matched closely with a German thinking of the interwar period through the mid war, the primary difference being that where the Germans talked of moving companies around, the US talked in terms of battalions.Near as I can tell, this misconception came about as a combination of a misunderstanding of what tank destroyers were supposed to do (hey, it’s in the name, right?) as well as a post-facto justification as to why US tank guns seemed to come off worse in a direct comparison to their German counterparts.

There’s a lot of misconceptions about what is or is not a tank, and this is especially relevant where tanks and tank destroyers intersect. The StuG III, during its lifetime, crossed numerous such lines, and built a purpose for itself everywhere it went. The StuG III was a true workhorse in all of the roles it filled, and today we’ll be looking at why it was built and how it was used, in order to answer your question. For this article, I will be using the great illustrations found on the website “Tank Encyclopedia.”As an Assault Gun. The Stug III, based on the Panzer III chassis, was an assault gun, one of the first of its kind. It was built, as all following assault guns, to support the infantry by destroying bunkers, machine gun emplacements, and anything that could be a hassle. The gun was mounted in a fixed casemate, which had two effects. The first was a cheaper production process, due to the elimination of a turret ring. The second was the ability to mount a larger armament than the Panzer III off of which it was based. In this case, the StuG III mounted a short-barreled 75 mm, ideal for shooting slow-moving high-explosive (HE) shells. For this period of WWII, the StuG III was well armed and armored, for it’s roll, and was fairly successful. During this part of the vehicle’s life, it was solely built for infantry support. This was the initial purpose of the vehicle.As a Tank Destroyer. The StuG’s mission would begin to creep from assault gun to tank destroyer with the introduction of vehicles like the StuG III F, bearing a long-barreled 75 mm. While it still could be used as an assault gun, it had become much more ideal than its previous variants at engaging enemy tanks. StuG IIIs had a long production run during WWII, due in no small part to their lower cost, and many began to live as dedicated tank destroyers more than infantry support tools. One way in which this change can be seen is in the reworks that were applied to the roof, hatches, and optics. By 1943, StuG III Ausf. Gs were being equipped with commander’s cupolas, a clear sign of their shift from assault gun to tank destroyer. Now, the StuG III’s purpose was tank hunting.As a Tank. Inevitably, the cheaper cost of the StuG III allowed it to replace tanks, due to their availability. The vehicle had a fairly powerful armament, and was fairly potent in a tank-like role, despite lacking a rotating turret. This happened increasingly often as Germany’s war industry weakened from allied bombings towards the end of the war. At this point, a StuG was assault gun, tank destroyer, and tank (better than judge, jury, and executioner).So now that we’ve answered the first part of the question, we’ll answer the last bit. Especially towards the end of the war, the StuG III was just another tank. Anything that Germany could use to desperately hold the line would be used, and StuGs served in a tank’s shoes up until the very end.What was it? It’s considered an assault gun or tank destroyer because these roles were what it was built/modified to do. Doctrine is what defines an assault gun or tank, and the StuG was built for the assault gun role. The mission of a tank destroyer came naturally with armament upgrade, but the role of a tank was an improvisation with no modification. They would simply take a StuG III and use it as a tank, and while this could work, it wasn’t the intended purpose. It was built to be an assault gun, and so that’s what it is. Hope this helps.