Is the T-34's gun really under modeled in the game??

[jaeger8888]

As I've already stated, the Tiger and Stugs are way too resistant to damage.

Wanted to know what all the fuss was about and wanted to do my own research. Sorry if its all too jarring for your ego. Obviously the gentlemen who opened this thread certainly wasn't aware of the problems with the game and decided to ask. If that is how you respond to people looking for help or a better understanding of the game, its amazing anyone would ever want to discuss anything on this forum. If that's how you respond to people I'm surprised that you've lived this long, but I'm sure you're not that brave in real life.

jaeger doesn't know that formula aren't physics.

Physicists know this.

But the reason the 30+50 StuG is impenetrable isn't physics or a standard formula, nor a software issue as he supposes. It is much simpler than that. 30+50 ought to resist like about 75mm solid plate, according to all the standard naval formulas. In the game is resists more like 90 to 95mm of solid plate. And the reason is the designers listened to "German physics" BS from a design advisor, and everyone else involved in this discussion knows every syllable of it, chapter and verse. It's nonsense.

Now, is jaeger8888 going to agree to the recommendation that German players fight in Panzer IV longs in 1943? Or is he going to defend cherry picking only Tigers or broken StuGs?

If he still can't make up his mind, put either an "early mid" StuG or a Tiger I in a lane with SU-85s in 1943. Not 1944 (the ammo modeling matters by year). Try Russian 85mm AA too, against both. Vary the range from 1200 meters down to 600 meters in 200 meter increments. Then come back and tell us there is no issue, again.

Newbies need their teeth straightened, but after five or six years it gets tiresome. You aren't god's gift and we aren't idiots, we know *exactly* what we are talking about. You - don't.

[ArgusEye]

It's hard to keep track of everything argued on this thread, so I apologize if I inappropriately ignore an argument made earlier.

When you line up all the different StuGIII's, and shoot them from the front with a T34/76, the 50mm StuG gets killed at range, the 80mm StuGs get partially penetrated to death around 500 meters, and the 50+30 StuGs are all but invulnerable. That the 50+30 is inappropriately tough is obvious, but it's more interesting to look at the 80mm StuG. What is supposed to happen?

The only definitive answer can be given by tests performed at the time, with appropriate experimental methods. Things like that were performed, but I've been unable to find any documentation thus far.

Testing penetration was done by all sides, but unfortunately, they used different test protocols, making them hard to compare. Even more unfortunately, I haven't succeeded in finding a complete specification of Soviet tests. Comparing the test plate of the Soviet tests with the actual StuG frontal armour would then at least be possible.

The KwK40/L43 penetrates 115mm at 0 degrees. The projectile, massing 6.8kg leaves the barrel at 745m/s. The F34 shoots its standard AP projectile of 6.3kg at 655m/s. If we assume they lose the same percentage of their energy in the 500 meters of air they tunnel through (they won't, but let's pretend), the Soviet round impacts with 72% of the energy of the German round. If we assume the round quality of the Soviet round to be so much better as to achieve the same penetration mode profile (which is hard to believe, but again: let's pretend), we may grosso modo equate penetration depth to impact energy. This results in an estimated penetration of 83mm. That means full penetrations at 500 meters - but only just.

The aerodynamics of both rounds is too complex to attack theoretically, so I'm not going to fine-tune that aspect of the above assumptions. What we can compare easily is the penetrator geometries.

The BR-350A is a flat-faced penetrator. This is done in order to ameliorate shattering propensities, but it restricts the penetration mode profile to plugging most of the way through. This is an energy-inefficient way of penetrating, but it allows use against very hard armours.

The PzGr39 is an ogival penetrator. This geometry is more susceptible to shattering, but if that is avoided, it pierces before it starts plugging, which is a more effective method of penetrating armour. With the same energy, it will therefore penetrate deeper. How much deeper depends greatly on armour quality, and on penetrator overmatch. There will be little appreciable piercing or plugging with low-quality or thin armour.

This points to the PzGr being more efficient. We should therefore subtract some portion of our estimate to correct for penetrator quality. How much this is in this case is very hard to compute, but we can try to find a lower limit.

According to the Curtis/Taub penetration model, we can assume the PzGr to pierce for 49mm before plugging the rest of the way. It is tricky to estimate how far the BR350A will pierce, but let us be generous and say that the B350A will still pierce half of the way throught the plate. Applying the aforementioned penetration model, one finds that the PzGr would penetrate 1.2 times as far. This adjusts the estimate of the BR350A down to 70mm, well under the required thickness, causing partial penetrations at most.

Armour quality figures into this as well, but again a lack of data hampers analysis. Going only by listed hardness of the German test plate and the actual armour of the StuG, we see that the Germans used softer armour for the StuG than as test plate. This suggests that our projectiles would penetrate slightly deeper into the StuG than into the test plate. This would bump the BR350A's chances of penetration up again. If I go by the Brinell hardnesses listed on http://www.freeweb.hu/gva/weapons/german_hardness_gun.html , I arrive to a modeled penetration of 78mm in StuG armour.

This is the fruit of an awful lot of assumptions, and an awful lot of different parameters that have more or less dependence upon each other. Even the model -though the most advanced published thus far- is crude at best. So this cannot be taken as having any kind of precision. However, I have been kind to the Soviet projectile, and still it only barely penetrates. As such, the theory would suggest that StuG armour would get mauled badly by the T34 at 500 meters, but there is by no means certainty that the rounds will go through.

The bottom line to this is that from a theoretical standpoint, the F34 does not seem to have been shortchanged. Only the 50+30 is obviously overmodeled. The game does not model softening of the armour after multiple hits to a plate, which would make things easier for the T34.

By the way, has anyone else noticed that a knocked-out or abandoned tank seems to be penetrated more easily?

[mxh123]

Let me know if interested, PM or email me back.

I am sure that Moon can help you out somehow regarding a manual for Combat Mission.

[JasonC]

ArgusEye - on what is supposed to happen: "at a range of 500 meters, the armor of the assault gun provides *no protection* against Russian tank guns".

Contemporary. German. Training. Document.

To jaegar8888 - the thread is nearly *3 years old*. And it wasn't remotely the first. This subject has been hashed out completely, by experts on both the history and the game, for eons. If you come in after all of that, you might bother to read some of it. Instead of pretending that none of us said anything or supported any of it.

Me, I get tired of a subject like this after oh I don't know, about 9 months (lol).

Especially when no one - no one - jumping into any of it starts by saying "oh yeah sure, I can see taking Panzer IVs in 1943, those are fine..." Instead it is always pulling teeth to get anyone to confess to game breaking bug exploiting cherry picking, or that it might be a problem, maybe even one that common sense players actually interested in having an opponent might want to be accomodating about.

Why on earth is it so hard to get people to just say "sure, I'll drive Marders and Panzer IIIs in 1942, and Panzer IV longs in 1943 - that's mostly what they had anyway, right?"

Jeesso flip, "it makka tha ganglia twitch..."

[ArgusEye]

ArgusEye - on what is supposed to happen: "at a range of 500 meters, the armor of the assault gun provides *no protection* against Russian tank guns".

Contemporary. German. Training. Document.

Great! Where can I get this document? I've not been able to find anything primary regarding StuG doctrine.

[JasonC]

"The German Sturmgeschutze in WW II", by Wolfgang Fleischer, with Richard Eiermann.

Some highlights -

pp 74-76 says with the long 75, fire at enemy AFVs at ranges beyond 1500m was discouraged as ineffective and a waste of ammo, because AP would fail to penetrate even with a hit.

p. 84 says the 80mm front models "could withstand the fire of the 76.2mm tank gun of the Russian T-34 if it did not come within 500m." Says the same was true for the ZIS-3. It also mentions a weakness in the gun cradle armor, only 45-50mm (much like the turret of a Pz IV incidentally).

p. 87 discussing the StuH talks about its weakness vs. enemy armor, because the low muzzle velocity of its HEAT ammo made it accurate vs a vehicle target only at about 500m (~1 second flight time). "At distances under 500m, as was already noted elsewhere, the front armor of the assault gun offered no protection from the fire of tank guns."

p. 117 says flatly that the 75L48 with Pz Gr 39 could not penetrate the IS-2 from the front, even at a range of 100m. Nearby, an AAR mentions a StuG killing an IS-2 with its 5th hit after the first 4 bounced, without specifying which plate was struck.

p. 127 shows an 80mm front StuG-IV model with track sections on its bow and concrete reinforcements.

Later in the book, the improved effectiveness of the later Allied guns, the US 76mm and the Russian 85mm, is described as their new ability to fight from long range, not needing to close. Not as the first ability to penetrate from the front.

[dieseltaylor]

Good stuff. I imagine every AAFV has the chance of a shell going into the turret ring/under the mantlet and I imagine every tank gunner was taught were to aim on targets that were "tricky".

[Michael Emrys]

...I imagine every tank gunner was taught were to aim on targets that were "tricky".

And defensively, the drivers were taught that whenever possible to halt the vehicle at a modest off-angle to the source of enemy fire rather than face-on. That effectively increased the slope of the armor. I wonder if that is still being taught in armor schools.

Michael

[ArgusEye]

JasonC - are you referring to 'The German Sturmgeschutze in World War II, 1939 - 1945, A Photo Chronicle' by Fleischer & Eiermann? What I was actually looking for was the training document you referred to earlier. The above quotes seem to come -if I am not mistaken- from a secondary source. Or are these statements referenced to a primary source?

[JasonC]

The training document it quoted in the book. It is a German tactical advice document about the StuH and its proper use and role, and the piece in question is specifically discussing the suitability of the StuH for anti-tank uses. It is explaining why it is a Bad Idea to try to use the StuH for AT roles. The penetration is no problem, 105mm HEAT does the job if it hits. But the muzzle velocity is low enough that the preferred engagement range with HEAT is 500 meters. Fighting at 500 meters is a Bad Idea because, you guessed it, "at 500 meters the armor of the assault gun provides no protection from Russian tank guns". Ergo, don't go toe to toe with T-34s in a StuH, because they will either be so far away you won't hit them, or so close they can kill you.

[Sergei]

And defensively, the drivers were taught that whenever possible to halt the vehicle at a modest off-angle to the source of enemy fire rather than face-on. That effectively increased the slope of the armor. I wonder if that is still being taught in armor schools.

Michael

This sounds like something that works better in theory than in practise, though. First of all, for the driver it's hard to even tell the enemy direction that well. If the enemy comes on a wide frontage, you can't be at a slight off-angle to all of them. Conversely, it's unlikely that you'd ever be perfectly perpendicular to any target. Trying to get to an off-angle also runs the risk of exposing the thinner side armour to hits, as well as make your vehicle a bigger target. But perhaps most importantly, the driver would have been very busy with his main job, that is getting the tank moving forward/backward as soon as ordered, and I think you'd want to have the tank oriented so that you only need to step on the pedal without time-taking maneuvering.

[JasonC]

"I wonder if that is still being taught in armor schools."

It is. Moreover, for a long time (until the latest model basically), the M1 in particular had a significant shot trap right under the gun, where Russian 120mm HVAP could penetrate successfully after deflecting downward, and the exposure of this shot trap could be minimized by engaging with the turret rotated well off the straight-ahead position over the hull - and this was taught in the armor schools.

[Vark]

Tiger tanks used the off-angle tactic, with the reinforced mantlet pointing toward the likely enemy and the hull turned slightly. It was often used when the Tiger had one flank protected by a terrain feature or structure, using it in CMBB (with the turret on a slight cover arc) seems to work in mid-44 scenarios.

[Vark]

Jason, I assume you meant the Russian APFSDS 125mm?

[Michael Emrys]

First of all, for the driver it's hard to even tell the enemy direction that well.

Which is why the vehicle commander is calling the turn. "Turn, turn, stop!" Granted, all this is practical only when there is enough time for this kind of careful placement, but that would be a great deal of the time.

Trying to get to an off-angle also runs the risk of exposing the thinner side armour to hits, as well as make your vehicle a bigger target.

Of course, which is why only a slight angle was used, probably in the neighborhood of 20-30°. Any hits on the side armor strike it at such a shallow angle as to ricochet without much chance of penetrating.

One caveat you do not mention is that this only works really well with turreted vehicles. Anything with a limited traverse would run the risk of a potential target either popping up or moving out of the field of fire.

Michael

[ArgusEye]

Finding information about the StuG is rather more difficult than about, say, a Panther, Tiger, Sherman or T-34. That much is clear so far. I took me a while to get my hands on some more documentation, after JasonC's hints.

The only document that JasonC's quotes could come from - that I could find - was Richtlinien für den Einsatz der Sturmgeschütz-Einheit, of which I have only been able to find translated fragments. If anyone could point me to the original, I would be very happy. This is no training document, it is a guideline for the divisional staff.

What is interesting about this document, is that it came in two editions: one in May of 1940, and one in March (or April) of 1942. Even at the time of the latter, the StuG's only had 50mm or 30+20mm fronts, as the first F's were only just coming off the assembly line. Indeed, this document does not seem to be written for anything else than the short StuGs, and to apply its teachings with a broad brush to any StuG is going a bit too far.

The comment about not engaging targets beyond certain ranges is mentioned here also, but one can understand that given the short 75's meager performance.

What is more interesting is that in pursuing the above document, I came across actual test results by Wa Prüf 1 in August of 1944, where they shot up StuGs with captured weapons. Unfortunately, the result list does not mention the F34, but it makes a passing comment that its performance limits are 'well known'. :mad:

Make of it what you will, but the front of the StuG is listed as vulnerable

to the American M3 at ranges up to 100 meters when using M72 ammunition,

to the American M1A1 at ranges up to 1700m when using M93 ammunition,

to the Soviet S53 at ranges up to 1500m when using BR-365 ammunition, and

to the Soviet A19 at all ranges.

Now for a more problematic issue: JasonC listed the quote

"at a range of 500 meters, the armor of the assault gun provides *no protection* against Russian tank guns".

I am tending towards ascribing this statement to the judgement of mssrs. Fleischer and Eiermann. There is no statement to this effect in the documents I've come across thus far. It is obvious that for a 50 or 30+20 StuG it would have been suicidal to duel with a T34, but for later models this remains to be seen. As for the armour of any vehicle, there is a range where one does not have to worry about impacts, a region where one is safe against the occasional hit, but the armour can be chewed up beyond repair, and a region where the rounds will come through the armour. One could say that the quoted statement suggests that at 500 meters the StuG is well within the penetration range, and that is something that needs to be researched a little more thoroughly.

As for the statement that the long 75 (I assume the L48 {because I have data for it }) does not penetrate beyond 1500 meters, I would concur if we are referring to frontal aspect shots. If a side is presented, the L48 holes the T34/85 up to 3000 meters, and the Sherman M4A4 at similar ranges. The question becomes whether a hit can be scored, and that can be tricky enough to forbid the use of ammunition for such long shots. This data is again from direct tests by Wa Prüf 1.

Also interestingly (but as an aside from the topic of this thread) a Wa Prüf 1 document from November 1944 states that troops in the field are adding concrete onto their vehicles after the cancellation of Zimmerit, mostly because it was thought to defend against bazooka's. Wa Prüf 1 discouraged this because it weighed the vehicles down unnecessarily, and actually deteriorated its protection (although they don't specify how exactly). To put forward that the tracks and concrete are evidence of poor amouring ignores that there are even photos of IS-2 tanks with track links on the hull front. It's all just part of that sensible human sentiment of wanting as much metal as possible between you and the shell screeching towards you.

But in the end, it can be said that any hit is liable to be bad, and that it is more important not to get hit than to be better armoured. Its far superior optics are likely to have saved many more StuGs than its armour.

[dieseltaylor]

“Saukopf”

Saukopf is a term invented in postwar literature. The name used in the German reports for the cast gun mantlet on the Sturmgeschütz was “Topfblende” (pot mantlet) (Jentz).

http://stugiii.com/home.html

Interesting stuff if not directly to the point. the additional time to add Zimmeritt is a laugh.

[dieseltaylor]

http://www.historyfacts.biz/en/04_Publikationen/LeseprobeStuGIII/StuG%20III%20History%205%20Combat.pdf

Some interesting snippets.

The authors are quite fun ...

Are our Assault Gun III books plagiarisms?

In the internet forum Missing-Lynx a certain Mr. X, writing under the pseudonym "Jack Reacher" and using a hacked IP-address of a friend of us, stated that both our StuG books would be plagiarism (copies), using books of Thomas Jents and Walter Spielberger, the drawings we should have stolen from Hilary Doyle's publications and we should have only modifyed them a bit before publishing. Altough the dicussion moved into a good direction for our work and us - thanks a lot to our readers posting theyr opinions! - we'd like to place our statement here:

Right from the beginning of our research, we decided to base on primary sources and not on existing literature, to avoid falling in the same traps as other authors did - perhaps we found new ones? The list of sources you'd find here.That we own an know most (if not all) of the existing StuG literature, our readers can be sure. The list of literature is published in Volume I. In addition we'd like to diagnose, that Spielberger's book, with aprox. 140 pages covering the StuG III (the other part was about StuG IV, support vehicles e.g.) was the longest piece of writing about the topic, all other publications were much shorter. It would have been quite tricky to publish some 600 pages just copying the other authors, would'nt it? The photographs we used were from our collection, some archives and lent by some gentle, well known photo collectors.

Concerning the drawings we wanted to publish, we decided to start with a blank sheet, working from scratch. Mr. Hilary Doyle's drawings were absolutely no root for these drawings, not to speak of "modifying them a bit". In addition to that, we publish more and other drawings (most of them in Volume II), than any other author ever did. The differnces between Doyle's and our own drawings are so evdent, that Mr. X must be blind:

[ArgusEye]

Some more digging turned up the following:

From Nachrichtenblatt der Panzertruppen, may 1944, the following exerpts of the section Erfahrungen mit Sturmgeschützen:

1. Russian tanks are no problem for us! When the situation allows, wait and let them approach! Broken-through tanks are completely helpless. At night, only open fire after positive identification! Roll in quietly. Always camouflage paint when there is snow. Caution when a tank seems to have been killed! Immediately shoot until it's on fire, or get the Pioniere to blow it up.

[...]

10. With artillery and PAK-fire, often make little position changes to get out of the crosshairs of the enemy. N e v e r t u r n p e r p e n d i c u l a r , always show them the strong front.

[...]

12 When s h o o t i n g a t P A K alternately fire HE and AP grenades. When there are ricochets, cut the range by at least 50 meters.

[...]

Nice peppy tone, so it's not unlikely that it's stained with some unmerited optimism - but it's been approved by Guderian, so it can't be all that bad.

In another Nachrichtenblatt der Panzertruppen, this one of april 1944, a translation is shown of a Russian publication:

Russian Guidelines for Combating German Sturmgeschütze.

In the Russian Artillery-magazine of may/june 1943, the essay of a lieutenant-colonel is published: "combating German Sturmgeschütze", in which the following guidelines are given:

The peculiarities of StuGs and their great maneuverability on the battlefield make apparent that it is purposeful to deploy special batteries and sections, which fire from hidden positions, to combat StuGs. These batteries and sections need to have special observers at their disposal, who are to announce the arrival of StuGs in a timely manner, or immediately open fire upon them.

In the defensive fight, the best results against StuGs are achieved by construction of a system of support points. These support points are erected behind artificial or natural obstacles, and deeply layered.

[discussion about StuG assault forms and mine placement omitted - too much translation work.]

With a system like this, the fire of our hidden positions needs to be directed onto all waves of the attack. In this case, the heaviest fire should be reserved for the second and third wave of StuGs. Mortars, and at closer range MG's, are to combat the accompanying engineers. This will allow our PAKs, in advantageous cases, to combat the StuGs of the first wave by direct fire. With this it is necessary to warn against the often-made mistake of opening fire at ranges beyond 1.5km, because this is less than effective and shows the enemy the disposition of our guns.

[exposition about the exact form of artillery fire used to blind and tie down StuGs omitted - suffice it to say that artillery is used to allow PAKs to shoot without being immediately suppressed]

In case of breakthrough the StuGs are to be taken under fire not only by artillery and ATR's, but also by small arms. The combined fire of machineguns and rifles at the crews of StuGs is already effective at a range of 400 meters, and can induce the crew to bail out. At short ranges, the hand grenade can be successfully deployed.

When StuGs come under artillery fire, they usually stop and try to take cover in depressions. With this they don't turn around, but reverse whilst fire ready. Since they can only be successfully attacked from the sides and rear, it is necessary to deploy AT forces to be passed by. With regard to this, it is important to take care, since the StuGs take suspicious positions under fire from considerations of caution.

[part about killing munition carriers omitted]

Experience has taught thet the Germans apply StuGs together with infantry, tanks and artillery. [...] For these purposes, it is necessary that attacking forces are reinforced with special forces for the destruction of StuGs. Escort guns and ATRs have to be constantly on hand to repel StuGs.

The Germans count the StuG as offensive weapons. Regardless, they have in the winter of this year widely used them as cover for retreats and rear guards. Leading element PAK and ATR's have, in cooperation with infantry and tanks, successfully attacked the rear and sides of the deployed StuGs.

Shows a certain amount of trouble caused by the StuG. Guderian makes some comments, of which one is interesting:

3. In combat, the sideways support of Sturmgeschütze must always be secured.

The armour does not make invulnerable!

Therefore: use the terrain, observe, when under direct fire don't "play bullseye", watch for enemy close assault teams!

Fire and movement, quick understanding of each situation, joy of taking decision, gung-ho attitude, coupled with rational consideration must be the characteristics of the combat method of the Sturmgeschütz.

A report to the command of 14. PzDiv (of which I have only snippets) of january 1944 by a company commander states that interrogation of captured T34 crews turned up that:

the Sturmgeschütze are vulnerable from the flanks, but usually have PAK and other StuGs covering their flanks. If possible, one is to gain position to the flanks of the StuG. Otherwise, the StuG is to be blinded with HE, while approach is sought to a distance of 300 meters at which range the StuG front can be penetrated. Subcaliber ammunition is not to be used at ranges exceeding 500 meters.

This one is German claims about claims made by a prisoner, which comes from a typed sheet from an auction website - not the greatest reference.

Sideways relevant: a Russian publication about firing tests against a Tiger tank, of april 20 1943. Tiger armour might be of better quality than a StuG front, but I am not sure of this. Cutting to the chase, this list of vulnerable targets for each gun might be interesting:

57mm:

with AP: sides, rear from 600 meters

with subcaliber AP: sides, rear from 700 meters, front from 100 meters

76mm mod 1942

with AP: running gear, turret ring, gun

with subcaliber AP: sides, rear from 700 meters, front from 100 meters

76mm AA gun

with AP: sides and rear from 500 meters

with subcaliber AP: front from 700 meters (no listing for sides or rear)

85mm AA gun

with AP: sides and rear from 100 meters

From all I've been able to find thus far, it doesn't seem that the F34 is undermodeled at all. It does what it's supposed to do, as long as it doesn't go up against the faulty bolted-on armour. I find it a bit far-fetched to accuse the designers of bias against the Russians.

[Kineas]

Good info, thanks.

I don't necessarily consider phrases in training manuals like 'under 500 meters the armor provides no protection' as reliable information. It's more like establishing a doctrine for the tankers, they wanted to err on the safe side of things etc.

What's remarkable is that wargames model the T34-Stug force relationship very differently. In the CM model the Russian tanks die easily. In Steel Panthers it's almos impossible to get a kill over 1km (Stug 75mm long, T34 front, the usual setup), and even 88m bounces quite often. Stugs seem more vulnerable than in CM, but not much. I guess the "truth" is somewhere in between, I don't think we get any closer unless we get together in a tank museum and start blowing things up.

[Wrath of Dagon]

Are 76mm and 85mm AA above reversed?

[ArgusEye]

It's weird, isn't it? They are not reversed, it is how it appears in the original text. Neither is it corrected in the errata in the next issue. There is no explanation, just this listing. I'm keeping an eye open for an explanation.

[Redwolf]

Must be HE for the 85mm.

Obviously AP for the various 76mm is not so weak that you must be at 500m to penetrate from the sides.

[ArgusEye]

Not even HE, it's the original UBR-365.

A full weekend (miss)spent on researching another comment from the first post of this thread: the 85mm gun being nerfed until 1944, has brought me a heap of confusion.

Where the German sources are usually quite consistent - although biased in their own way - the Russian sources contradict each other and the reports from the Western allies a great deal. It doesn't help any that I don't read Russian, either.

There are very few original documents to be had about early 85mm performance, most of the information I have comes from secondary sources. Most of them Russian. The few primary sources I have tracked down are a Wa Prüf 1 test with captured SU85, which had most of its ammunition breaking up when shot at any surface hardened plate thicker than 80mm, and some UN tests of captured North Korean materiel in 1953. Oddly, even though the UBR-365 is listed by most lists as APBC and the UBR-365K as APCBC, the UN analysis shows both rounds to be uncapped solid steel AP.

Inasfar as it is prudent to draw any conclusions at all from the material I've had access to, it seems that the 85mm AA gun had great AP effect against targets it overmatched greatly, but failed miserably against heavier armour. Its transformation into a tank gun failed (somehow, nobody is too clear about this), so that new models of 85mm caliber had to be developed. Several models were developed, but the first one to reach production was the D5-T.

Then there are some confused statements in a few Russian books that there was a decision to build a gun to match the performance of the 8,8cm/L71, but this gun was either canceled, never attained the performance desired, or kicked ass and was inexplicably never heard from again. One source grumbles about the order to base the gun around the AA gun shell was ill-suited to a tank gun, but again there is no consistency between writers.

There is mention of vague 'problems' with the first operational guns by most writers, but they don't specify - again. The anti-armour performance seems to have been problematic, gun longevity is mentioned by some scholars as being the bare minimum. Whether this applied to the prototypes only, or carried over into the production models is not clear.

In the SU85, the Germans recognized a dangerous opponent, and the Soviets a strong asset, but German testing with a captured example show projectile shattering problems in December of 1943. The Soviets had already been redesigning the ammunition since August. This did not bear fruit until January of 1944. Given that the gun had been designed around the ammunition, the change in ammunition is remarkable.

Likewise, there are multiple statements from scholars (again, I cannot find primary sources) that the 100mm gun was taken into development because the 85mm turned out to be 'unpromising' or 'obsolete' at this point.

The D5-T and the later improved ZIS-S-53 (which traded some ballistic performance for a lot of ergonomics) are depicted by both sides as big improvements on the weak F34. Regardless, the gun did not come close to the German guns, as was originally hoped. It was the strongest gun the T34 frame could bear, so it was used.

Problems with the gun start focused around its disappointing performance, but later these complaints disappear, and the general opinion shifts to the gun being the perfect mate for the T34. Things like inability to load on the move or failing recuperators are the new focus. This seems to support the CMBB case. The main praise for the gun by this time is its simplicity and firepower.

Much is unclear or confused, but it seems like there were severe ammunition problems until January 1944, and according to German tests, the modeling in CMBB is not bad. In fact, compared to Soviet tests from April '43, it might be optimistic. Again, there is not enough primary material available to me to make a sound judgement on this. If anyone could supply me with some primary sources or consistent scholars, I would be grateful.

[JasonC]

T-34/85s routinely clobbered King Tigers. Claims that they couldn't penetrate 80mm armor are hogwash. The Germans themselves report 80mm front StuGs became vulnerable at ranges out of 1.5 km against 85mm. As for the performance, it roughly matched not the 88L71 (absurd claim) but the 88L56. There is no appreciable difference in muzzle energy or anything else between the 88 Flak and the Russian 85mm.