Advice on t-34 vs STUGs???

[danielh]

Question to Rexford:

As i understand your post, the russians were mainly using APBC rounds for the 76mm T-34 guns. (armor piercing ballistic cap) With this they were barely able to defeat 50+30 FH armor only from very near.

What is the difference of this ammunition to US Ammo ? T-34/76 has muzzle velo of 690 m/s and is rated with 81 mm at 100m, whereas the M4A2 gun has 619 m/s but penetrates 90 mm (In theory having same ammo T-34 gun should be better around a factor of up to 1.2) . Didn't the russians use armour piercing capped with ballistic cap ? Is the US figure vs. face hardenend ammo ?

But what really strikes me ist the fact that the 37mm gun of the Stuart is more powerful than the 76mm T-34 gun and on par with the one of the Sherman (penetrates 90 mm at mv of 880 m/s with AP shot)

The russian 37mm Flak gun also has a mv of 880 m/s but penetrates only 68 mm with AP shot. (Factor 1.3 lower)

Even more interesting is the fact that the russian 45mm/L66 penetrates 70 mm with AP shot at a mv of 820 m/s

In theory the russian 37mm and 45mm should be better or even with the Stuart's gun, the 45mm being superior, why that ?

Even more interesting is the fact that the Pak38 50mm with a mv of 835 m/s is on par with the Stuart's gun. Again in theory the 50 mm should be clearly superior to the 37mm of the Stuart by a factor of about 1.2 = 108 mm

Any explanations for this ?

Greets

Daniel

[Runyan99]

Originally posted by SWPIGWANG:

http://www.battlefield.ru/guns/defin_4.html

Russian Data....look it up

Using that data, and referring to the Certified Penetration Data (that is, 80% probability to penetrate) for the same gun at the same distance it shows

70mm for BR-350A ammo, and

75mm for BR-350B

Not wildly different from what I have already found.

In fact, the only way to get a number over 80mm is to use BR-350B and look for an Initial Penetration (20% penetration chance).

Still looks to me like CMBB isn't undermodeling the gun. CMBBs figure for the same gun at the same range is 73mm, which looks like an 'average' of the data between BR-350A and BR-350B.

[stikkypixie]

Originally posted by Runyan99:

</font><blockquote>quote:</font><hr />Originally posted by SWPIGWANG:

http://www.battlefield.ru/guns/defin_4.html

Russian Data....look it up

Using that data, and referring to the Certified Penetration Data (that is, 80% probability to penetrate) for the same gun at the same distance it shows

70mm for BR-350A ammo, and

75mm for BR-350B

Not wildly different from what I have already found.

In fact, the only way to get a number over 80mm is to use BR-350B and look for an Initial Penetration (20% penetration chance).

Still looks to me like CMBB isn't undermodeling the gun. CMBBs figure for the same gun at the same range is 73mm, which looks like an 'average' of the data between BR-350A and BR-350B. </font>

[flamingknives]

Originally posted by danielh:

Question to Rexford:

As i understand your post, the russians were mainly using APBC rounds for the 76mm T-34 guns. (armor piercing ballistic cap) With this they were barely able to defeat 50+30 FH armor only from very near.

What is the difference of this ammunition to US Ammo ? T-34/76 has muzzle velo of 690 m/s and is rated with 81 mm at 100m, whereas the M4A2 gun has 619 m/s but penetrates 90 mm (In theory having same ammo T-34 gun should be better around a factor of up to 1.2) . Didn't the russians use armour piercing capped with ballistic cap ? Is the US figure vs. face hardenend ammo ?

But what really strikes me ist the fact that the 37mm gun of the Stuart is more powerful than the 76mm T-34 gun and on par with the one of the Sherman (penetrates 90 mm at mv of 880 m/s with AP shot)

The russian 37mm Flak gun also has a mv of 880 m/s but penetrates only 68 mm with AP shot. (Factor 1.3 lower)

Even more interesting is the fact that the russian 45mm/L66 penetrates 70 mm with AP shot at a mv of 820 m/s

In theory the russian 37mm and 45mm should be better or even with the Stuart's gun, the 45mm being superior, why that ?

Even more interesting is the fact that the Pak38 50mm with a mv of 835 m/s is on par with the Stuart's gun. Again in theory the 50 mm should be clearly superior to the 37mm of the Stuart by a factor of about 1.2 = 108 mm

Any explanations for this ?

Greets

Daniel

I can supply a partial answer:

Shell weight varies between guns, as well as shell quality, both of which affect the performace. The AP round for the US 37mm is solid shot, which weighs more than the explosive shell favoured by the Russians and Germans. It therefore carries more energy and is stronger, both factors that increase the penetration, but reduce behind armour effect.

The same applies to an extent with the 75mm/76.2mm comparison, as the Soviet 76.2mm AP shell has an unusually large amount of HE filler.

You are only looking at a small portion of the relevant data (MV and penetration) when mass and behind armour effect are also significant

[JasonC]

Runyan99 - A. That is BR-350A. That is why they made B - capped. Arrrggghhh.

[JasonC]

danielh - "which suggest german "kill"-figures being quite accurate". Unadulterated horsefeathers. Nobodies own side claims have stood the test of period specific other side loss reports. Ever. Any side, any front, any arm, any battle. Ever. They are always high. Always. Usually by a factor of 2, sometimes by more.

That is why *German staff officers, during the war, gave their own claims a 50% haircut for all planning purposes*. Occasionally, we can find period of exceptionally accurate claims, when other side losses only run 170% of claims - that is rare. Only in propaganda and post war nationalist chest thumping idiocy are they cited as facts. If every German kill claim were accurate, every Allied AFV would have been destroyed 3 to 5 times over, and none would ever have been lost to non-combat causes.

Claims aren't kills. It doesn't matter whether the claim is reported by the inspectator general of ubermenschen and countersigned by Nietzsche's own second cousin's grandson. Claims are claims, and kills are kills. The only - only - reliable source for actual kills is reports of own side unit strengths by the side incurring the losses.

[danielh]

JasonC, come down

I've put "kill" in apostrophe meaning claim of course..

To the exagerated claims, as i stated they may be exagerated by 50% meaning 3000 vs. 6000 claimed for the 8 month in 44, which is still more then enough... (The russians producing more than 12'000 tanks in the same period).

On the other hand one can very good count the abandoned enemy tanks after a failed enemy attack, although a rarer ocurrence in 44 of course than in 1942 for instance.

Flamingknives: I also thought about weight of shot, hardness and the like, i only hope rexford can explain in detail.

Thx anyway !

[Runyan99]

Originally posted by JasonC:

Runyan99 - A. That is BR-350A. That is why they made B - capped. Arrrggghhh.

Right. I listed BR-350B also. Again, I found

70mm for BR-350A ammo, and

75mm for BR-350B

So, B does not appear to be a whole lot better than A, according to these numbers.

Now, if you cannot get penetrations at point blank range, maybe there is a problem. But at 500m it does not appear that either ammo type is likely to penetrate.

Specifically, it looks like BR-350B has about a 20% chance to penetrate 84mm at 500m.

Just barely enough then, to get through the 50+30 on the front of a Stug. Sometimes.

[ June 12, 2004, 08:39 PM: Message edited by: Runyan99 ]

[Panzer76]

Also note what is stated on the battlefield.ru site:

"Also, it is important to understand that realistic penetration values in 1941-1943 was reduced significantly due to low quality ammo."

[JasonC]

30+50 is not 80. (Also, most armor is not 100% quality). Rexford is about the only man on earth who thinks it is. He is given to maintaining that layer cake armor outperforms an intact plate. The Germans just never noticed this when their lives depended on it, and went to uniform plates instead every time they upgraded.

The last time we had this conversation, another armor grog Rexford invited to confirm his statements said 30+50 should resist about like 74mm. The US army estimated it at 71mm (see their handbook of German forces, the entry for the StuG). The naval equation would give the latter. I'm inclined to believe the former. But that is the right range.

And they don't go in 20% of the time, IP. They don't go in 10% of the time, Rexford's imaginary magic bullets to account for all the recorded penetrations. They don't go in on second or later hits, after the upper 30mm plate has been shattered.

They just don't go in. Neither do 1943 85mm AP at less than 1 km, which even Rexford agrees is wrong. But 30+50 apparently resists not like 80, nor like 74, nor like 71. It resists more like 92. Which is German physics and a fantasy.

Meanwhile, the 25 pdr round with less KE, and the US 75mm round with equivalent KE, outperform them. LL rounds with lower rated penetration outperform Russian 85mm. Because there is a uniform untermenschen factor that says easterners must lose, I suppose.

If Rexford believed his own numbers he would lobby for 1/4 to 1/3 of hits under 500m to penetrate. 10% magic bullets plus roughly 20% of the normal ones (IP), on the majority of the surface, and all the rest too on the small portion with only about 50mm armor. That's on first hits, and at a little over 500m (since IP is greater than thickness at that range). Second and subsequent hits, after the top 30mm plate has already been hit? Not modeled - course not.

Instead he spends his time chasing around skeptics like myself and defending the indefensible indestructible uber-StuG, which no one had ever heard of before CMBB. No one on earth. Finding a thousand quibbles all going one way to give him a 15% fudge factor - without ever cross checking it with the tactical evidence. Discounting all the ones going the other way (better ammo "oh that's rare, leave it out"). Oh, and advising me to bring up the ridiculous underperformance of the 85mm with the designers.

Rexford knows a lot of data. But honestly trying to get at a truthful picture he is not. Anything that might endanger his beloved Tigers from the side he would resist with the greatest imaginable tower of fudge. If a side effect is invulnerable uber-StuGs nobody ever heard of before, he can live with that. (They are in fact entirely separable questions, but why give an inch?)

All of which is entirely academic because nobody is going to revisit CMBB these days. But people still play CMBB. And those who always use StuGs are just pussies. Now, the faithful can indundate the thread with their spin once again. Asta.

[Runyan99]

If that is Spanish, it should be Hasta.

Anyway, I think you're probably right. Everyting I ever read leads me to believe that 50+30 does not perform like 80mm, but something less.

So it appears that common Russian ammo should penetrate 50+30 at about 500m something like 20% of the time. Just barely, but sometimes.

Not enough to call CMBB broken, or for me to lose any sleep. A very slight undermodel by BFC in this case.

[ June 13, 2004, 02:47 AM: Message edited by: Runyan99 ]

[John D Salt]

Originally posted by Runyan99:

[snips]Not enough to call CMBB broken, or for me to lose any sleep. A very slight undermodel by BFC in this case.

Deeply unfortunate that it should occur on such a very common gun/armour match-up, though.

All the best,

John.

[Vossiewulf]

MikeyD, wrt to shattering rounds, that's Jason's point- he's asserthing that they're using data on a non-capped round for a time period when the Russians were using capped rounds. The entire purpose of a cap (not a ballistic cap) is to prevent the penetrator from shattering.

[FM Paul Heinrik]

Over the weekend I tried running some sims of stugs vs t-34/76 and 76 at guns. I found it difficult to test because the ai would ignore orders I gave sometimes. I actually never saw a stug g receive a pentrating hit durning this test. stug f 30+50mm was hit and penetrated and the crew bailed. stug f 30mm was hit and destroyed numerous times. Through out this test the russians couldn't shoot straight. They would miss almost all the time and the stugs would kill them. With no ammo the stug crews would bail on the 1st shoots fired. The t34s didn't look so impressive, but the 76 AT guns would actually hit the stugs and killed the stug fs. Unfortunately, I couldn't get a 76mm gun to kill a stug g, but it has happened to me, once during a critical pt in a fight, a 76 AT blew up my stug g and was the turning pt of that battle.

I haven't played CM for a great length of time so I don't really know or see a big problem with the 76 modeling on the stug 30+50 front plate yet. I do see that if the problem exist that it could hinder the game, too bad, because it seems like an easy fix.

I usually only play battles with under 700 pts so after buying a company of infantry a few support mortors and mgs I don't have a lot of pts for armor, mainly I can only afford early stug f or pz III or even barely a couple of pz II. Rarely am I able to purchase a pz iv d or e plus some other afv. I like to at least field 2 tanks. Sometimes I find that a couple of pz IIs are better than 1 pz III or stug f.

[Panzer76]

FM Paul Heinrik, do disrespect, but as a new player, you are talking about things you dont understand. If you want to learn more about this particular subject, you can do a search on this forum.

[rexford]

Response to JasonC's comments:

"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."

Sometimes true. T34 glacis armor thickness varied from 42mm to 55mm, and the shots would certainly bounce off T34 hull fronts carrying 50mm+ armor.

Reports in Jentz indicate that the PzKpfw IV with the 75L43 penetrated the T34 at 1600m max range.

"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)."

The mantlet around the gun barrel was 50mm thick.

The 80mm areas that are sloped at 10 degrees from vertical are small areas with lots of bolt holes, and the driver area has that large cut-out for the driver viser. So edge effects and weak areas abound.

The upper superstructure on a StuG IIIG is made up of 50mm plates at 51 degrees slope, which resists 76.2mm hits like 74mm vertical. The 500m penetration of the 76.2mm is 75mm face-hardened, so data matches combat reports.

"p. 87 discussing the StuH talks about its weakness vs. enemy armor, because the low muzzle velocity of its HEAT ammo made it effective only at 500m. "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."

Could you give us the month and year of the above report.

"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."

Horsefeathers. Why do you believe everything you read without looking at the entire picture yourself.

The 75L48 APCBC could penetrate the IS-2 mantlet and turret front beyond 900m if the impact angle were not too large. Look at the data in CMBB. Mantlet and turret front are 110mm and 100mm of high hardness armor, and the armor on the early versions was inferior and prone to flaking.

Furthermore, Russian tests with a 76.2mm gun against the IS tank showed that partial penetrations were obtained, and that gun penetrates alot less than the 75L48. The IS tank being fired upon suffered horrendous internal armor flaking within the turret.

See the IS development article on the Russian Battlefield site for some more discussion on the 76.2mm firing trials against the IS tank.

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

So what?

Face-hardened armor is damaged when it stops a round, and track sections and concrete would reduce the damage to the armor on non-penetrating hits.

"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."

We accept that the 76.2mm should penetrate the StuG IIIG front inside 500m. Have you tried to convince the designers that a change to CMBB is warranted?

[rexford]

Originally posted by Runyan99:

If that is Spanish, it should be Hasta.

Anyway, I think you're probably right. Everyting I ever read leads me to believe that 50+30 does not perform like 80mm, but something less.

So it appears that common Russian ammo should penetrate 50+30 at about 500m something like 20% of the time. Just barely, but sometimes.

Not enough to call CMBB broken, or for me to lose any sleep. A very slight undermodel by BFC in this case.

British tests against 30mm over 30mm on the PzKpfw IIIH, with 37mm thru 75mm guns, shows that the combo resists like a single face-hardened plate with 69mm thickness.

American tests against the 30mm over 50mm on the front of PzKpfw IV showed that the combo had more resistance than a single 80mm face-hardened plate.

Face-hardened plates in contact resist like more than the total thickness, homogeneous plates in contact resist like less.

Here's why.

The resistance on the surface of a homogeneous plate is less than the interior because the surface material is not held as tight lyin place by surrounding steel, so it is easier to push aside. With two 40mm homogeneous plates in contact there are four surfaces, whereas a single 80mm homogeneous plate has two surfaces.

With face-hardened armor, two 30mm plates in contact present more face-hardened layer thickness than a single 60mm plate, so there is more resistance.

Firing tests prove the above theories.

[edgars]

Face-hardened plates in contact resist like more than the total thickness

So why this feature has not been used extensively for other vehicles? Say, why Tiger front is 102mm, not something like 52+50 face-hardened?

And second question, how are those combined plates actually made? One plate is simply bolted on to another?

[flamingknives]

The extensive use of composite plates on modern MBTs indicate that it has been used by other vehicles. The problem is that a hit to the outer plate can damage the fixings that attach it to the main structure.

Of more relevance to WWII designs, the thinner plate that makes up the structure is less rigid than a thicker, homogenous, plate so more internal structure is required to maintain sufficient structural strength. You thus get an overall heavier tank of which a smaller proportion can be armour mass.

[rexford]

Originally posted by JasonC:

Runyan99 - A. That is BR-350A. That is why they made B - capped. Arrrggghhh.

The basic BR-350, BR-350A and Br-350B APBC rounds are all similar in shape (flat nose) and nose hardness, and they do not have an armor piercing cap. They have a ballistic cap which is a thin collapsible wind screen to reduce air resistance.

American 75mm APCBC penetrates 95mm face-hardened at 500m while BR-350B penetrates about 83mm of the same armor at 0m. The difference is due to:

1. American 75mm APCBC is at 54.5 Rockwell C nose hardness, Russian 76.2mm APBC is at 50 Rockwell C. Softer rounds penetrate less.

2. American APCBC has an armor piercing cap which protects the nose from the damaging effects of face-hardened armor, while Russian 76.2mm APBC does not have an armor piercing cap.

Face-hardened armor depends upon significant damage to the projectile nose to defeat hits, that's how it works. Anything that protects the ammo from break-up or shatter increases the penetration of face-hardened armor.

Homogeneous armor depends upon energy absorption to stop hits, that's why the armor is softer than face-hardened so rounds can partially penetrate and use energy pushing armor out of the way.

An armor piercing cap uses up more energy penetrating homogeneous armor than it contributes, and that's why the Sherman 75mm APCBC penetrates 82mm homogeneous at 500m and 95mm face-hardened.

The Russians did not use armor piercing caps during WW II.

During late 1943, the Russians super hardened the BR-350B rounds and increased the penetration by about 10%. Limited production. Probably not in CMBB.

The Russians also made 76.2mm solid shot with a pointy nose, which was designed to penetrate the Tiger side armor. Limited production, and probably doesn't show up in CMBB.

CMBB does not present both homogeneous and face-hardened armor penetration stats for guns, which can be confusing.

[imported_no_one]

rexford(and everyone),

I am going to ask the following questions/make the following comments with the assumption that you actually play this great game of CM.

Now,based on the evidence provided here,I dont see the t-34 versus the Stug-G as being that large of an unbalancing issue.

In the grand scope of CMBB,I dont see this as that big of a deal.Especially when you look at the undermodeled turret front of the PzIV.I mean the small size of it,plus the gun mantlet arent even taken into account,and in most years/cases it make the PzIV useless.

You add to this the fact that the russians get an armor point bonus,and I still dont see how its unfair.Its ok to have t-34s go up against tigers,that have to be taken out from side/rear shots,but its not ok to have to do the same thing on a turretless vehicle that is slow turning and has a 30 degree firing arc?

I just dont get it.

The dude that started this thread had atleast a 4:1 advantage of t-34 versus the Stug-G's.Now I dont know about terrain,or the number of ATGs or other German AFVs,but he had smoke,and clearly to me used a bad strategy.He even later admitted that himself.

The other aspect of the balanced/unbalanced issue is that most people dont look at it from a combined arms perspective.There are times that the russian forces have clear advantages over their German counterparts.It may be in a more robust infantry,or more on and off map 82mm mortar rounds,or C rounds in their t-34s.You cant win all battles with armor alone.

Early war russian infantry is brittle,and more proned to panic/rout.Late war germans are the same way,as a result of the fact that around '44 a 1/3 of the german infantry was made up of ethnic germans that didnt want to die for Hitler.I am not certain that this is modeled,but I can see a difference.

One important issue to remember is that you all need to be playing as large of engagements as possible.It is then that you will see how when used in a combined arms effort,there are big differences in each side depending on the year.Plus a StuG or Tiger on a hill at the back of the map will no longer be able to dominate the whole battlefield,but instead only areas of it.Flow around.

I believe that any person,whn playing person versus person,has an opportunity to prevail over his opponent.Its a matter of out-wit,out-think,out-play your opponent.Can you always overcome the odds?No,and I think this is pretty realistic.Its a matter of who has the right strategy,best execution of said strategy,and he who plays to the strengths and weaknesses of his forces best.Then you sometimes get lucky/unlucky.Learn and move on.

Isnt atleast some of what I say legit?

[/end truncated rant]

edit to add:

I would also like to say that I believe highly in advance/assualt operations.They do away with the whole flag concept and put the emphasis where it should be,forces versus forces,and terrain.

[ June 18, 2004, 01:35 PM: Message edited by: no_one ]

[Karl_Smasher]

Originally posted by JasonC:

30+50 is not 80. (Also, most armor is not 100% quality). Rexford is about the only man on earth who thinks it is.

Rexford knows a lot of data. But honestly trying to get at a truthful picture he is not. Anything that might endanger his beloved Tigers from the side he would resist with the greatest imaginable tower of fudge. If a side effect is invulnerable uber-StuGs nobody ever heard of before, he can live with that. (They are in fact entirely separable questions, but why give an inch?)

Why do you think that stug's penetrated from the front by 76mm would affect tiger side armor. Apart from the tiger's side armor being a single plate of RHA 82mm (not 80mm like stug) it was accoring to the BIOS report produced with the highest quality contorl of any german tanks/assault gun armor in the war, far better than the stugs.

There are Russian firing tests (Actual firing tests not estimates) from September 1943 (use search on forum) where Russian 76mm,57mm and 85mm guns failed to penetrate a captured tiger side armor at 100mm 0@degree angle. The side was only penetrated with an 85mm 'special round' at 200m.

[rexford]

Originally posted by danielh:

Question to Rexford:

But what really strikes me ist the fact that the 37mm gun of the Stuart is more powerful than the 76mm T-34 gun and on par with the one of the Sherman (penetrates 90 mm at mv of 880 m/s with AP shot)

Even more interesting is the fact that the Pak38 50mm with a mv of 835 m/s is on par with the Stuart's gun. Again in theory the 50 mm should be clearly superior to the 37mm of the Stuart by a factor of about 1.2 = 108 mm

Any explanations for this ?

Greets

Daniel

The 50mm Pak APC round should penetrate about 100mm at 0m and 0 degrees (homogeneous armor), while the Stuart 37mm APCBC round should penetrate about 80mm. The Stuart round is solid shot which gives it a small bonus compared to the 50mm PaK which contains a shell weakening HE cavity.

The T34 76.2mm APBC slightly outpenetrates the Stuart 37mm APCBC at point blank against face-hardened and homogeneous armor.

There was an uncapped Stuart 37mm AP round that penetrated about 94mm homogeneous at point blank.

[rexford]

JasonC stated:

"Rexford knows a lot of data. But honestly trying to get at a truthful picture he is not. Anything that might endanger his beloved Tigers from the side he would resist with the greatest imaginable tower of fudge."

British tests against PzKpfw IIIH showed that 30mm/30mm resisted like 69mm when all the plates are face-hardened. U.S. tests against PzKpfw IV 30mm/50mm showed that it resisted like more than 80mm with all plates face-hardened.

Instead of presenting firing test data that refutes the above tests, JasonC resorts to the above nonsense. Really very silly stuff, Jason.

And he is so confused.

PzKpfw IIIH and PzKpfw IV carried face-hardened armor on the front, the Tiger did not use any face-hardened armor at all. There is nothing in common between T34 penetrations against face-hardened layered plates and the side armor on the Tiger.

Jason, please try to argue logically and refrain from bad mouthing my efforts.

Okay?

[rexford]

Face-hardened armor is damaged when it defeats hits, and 30mm/30mm or 30mm/50mm combinations are a maintenance headache. That's why the combo armor layouts were eventually replaced with a single plate fo 50mm or 80mm thickness.

The Tiger was intended to drive into enemy positions and take tons of punishment from all sorts of guns, something that face-hardened armor would not stand up to for long.

The PzKpfw IIIH and IVG situation vs Tiger is similar to the T34 vs KV-I. The T34 carried very high hardness armor that did not stand up well against large caliber hits, even if they did not penetrate. The KV-I was meant to engage in slugfests and take repeated hits, so it used armor hardnesses similar to Tiger.