Tiger Fibel Notes on Tiger Accuracy

[Mr. Tittles]

Ive fired belt fed MGs with tracer and just from the tracer rounds that skip, its apparent that skipping is very common.

Its funny how 'intuitive' thinkers will say 'the ground must be hard to skip something off of'. Is water hard? Ive seen bullets skip off water.

Perhaps the angle is the most important factor.

[Mr. Tittles]

In naval warfare, skipping of short rounds (ie near the ship) is common. In fact, it would cause the base fuzes to misalign and NOT go off!

No one has supplied any data that skipping of German AP rounds will set them off. The only data shows that certain large capacity APHE shells will predetonate when striking armor. There is evidence of skipping AP rounds destroying/damaging AFVs.

[Mr. Tittles]

This is a 88mmL56 APHE (APCBC) round. It actually has a much larger cavity than a 75mmL48 (I have a pic of one in a book).

[undead reindeer cavalry]

Originally posted by ladoga:

just read article of finnish Stug commander Börje Brotell. He says that 1st round hits in combat were a norm. Also he mentions that they could hit black center area of 300m rifle target from 600m.

So i guess it depends much of the crew. With careful aim these guns were VERY accurate.

Lehväslaiho is claimed to have shot (or chopped), in a parade of some sort, a tree into one meter logs from 1000 meters (or some such range), and he was using Soviet guns & optics.

i don't know how credible such extreme claims are, but no doubt those gunners were exceptional marksmen, as shown by their records.

Finland had only a fistful of panzers & tanks, and thus could be very selective about the crews. you would become a gunner only if you had natural talent for it. perhaps other nations couldn't spare to be so selective about gunners?

anyways, in Finland the average armor-to-armor ranges were so short that i don't know if optics & guns mattered that much.

i have, as well, gotten the impression that 1st round hits were much more common than what we see in CM.

for what it's worth, i have also read reports of skipping rounds that penetrate the bottom of a tank.

[rexford]

Originally posted by flamingknives:

</font><blockquote>quote:</font><hr />Are your textbooks just your own version of 'Googling'?

In a manner of speaking, yes, although I tend to trust them more than internet sites.

The timing on an APHE shell is important because it is intended to detonate inside the tank. To skip a shell into a tank would require:

* That the ground is hard enough for the round to skip off

* That the angle is acute enough that the round will skip without being too damaged or the trajectory be altered too much (i.e. if the direction of travel is still along the long axis of the shell

* That the target tank is close enough that the shell will not detonate prior to hitting it. OR

* That the impact with the ground is not sufficient to trip the fuse. OR

* That even if detonated, the charge does not significantly alter the shell mass/shape/trajectory

As to whether the HE in an APHE shell is sufficient to reduce the shell so that it is not capable of further penetration, one would need to know the proportion of shell mass that is HE. If it is comparable to the US 75mm APCBC-HE, then one can conclude that the detonation would radically alter the shells mass.

No you are thinking incorrectly and you are probably a student with very little real world experience.

Real world experience? Of skipping 88mm APHE shells into tanks, no. I have no experience of that. Am I probably a student, or probably have little real world experience. As we're working with theory and history, it will suffice to prove me wrong rather than say that I'm wrong because I'm inexperienced. </font>

[rexford]

Originally posted by Mr. Tittles:

check panzer IV website.

As for your meandering into nose fuzes, its still has nothing to do with the topic. So what if they have settings? They are entirely different than base fuzes????

I think your posts may bring interesting data to the forefront, but your logic and technical skills are not up to the level needed to discuss these topics.

While I wasn't go to dignify your posts with a response, the personal comments above deserve one last post:

1. the Panzer IV Universe data on 75mm APCBC burster weight is wrong, the data was prepared in the 1960's and has been eclipsed by actual measurements taken during the war.

2. I lack logic and technical skills? Here are a few tidbits from my personal background:

licensed professional engineer

30 years studying armor penetration/projectiles

cowrote book WW II Ballistics: Armor & Gunnery

Derived slope multiplier and armor quality system used in Combat Mission games

Contributing editor to Campaign Magazine in 1970's and early 1980's

Over 35 published articles on WW II tank combat

Created the AFV Kill system used in Advanced Squad Lead

Member of playtest team on over 10 games

Like most of the other things you recently posted, your comment about my logical and technical skills is based on what appears to be an insufficient research effort.

[Mr. Tittles]

If an HE round will detonate on a glancing hit against the ground, why wouldn't APCBC?=rexford

If anything, this silly statement invalidates much of your resume.

[rexford]

Originally posted by Mr. Tittles:

If an HE round will detonate on a glancing hit against the ground, why wouldn't APCBC?=rexford

If anything, this silly statement invalidates much of your resume.

You were plain out wrong regarding my ability to analyze things, and calling my questions to you silly will not change things.

Asking a question is not taking a side or making a definite statement, so it is not as silly as you think. It is logical to ask if APCBC-HE will detonate on glancing ground hits since HE will.

Prove that it wouldn't detonate.

Don't just talk, show us the money! If you are so sure it will not detonate substantiate your statement.

I previously invited you to research the issue and get back to us, and eagerly await your findings.

[rexford]

Originally posted by Mr. Tittles:

The only data shows that certain large capacity APHE shells will predetonate when striking armor. There is evidence of skipping AP rounds destroying/damaging AFVs.

No, no, no!

The test data shows that the burster in APHE will detonate and go off after passing through a 20mm plate, and then the round will not be able to penetrate a 50mm plate 6" behind the first.

This is not predetonation, it is the normal action of an APHE fuze where the burster goes off after the round passes thru the armor.

The 90mm APCBC-HE round predetonated when it hit test plates during May 1944 trials, where the round failed to penetrate because the burster went off BEFORE penetration.

In the 75mm APCBC and Russian 122mm tests the burster went off after penetration, as it should.

Bye.

[Mr. Tittles]

Firstly, the most unbelievably obvious is that the HE shell has its fuze in the front and the AP shell, in the back. The HE shell is designed to work on delay after minimal contact, the AP shell is designed to detonate after a considerable contact. Your logic is quite off base. It isnt worth persuing this with you.

And, yes, I did provide info that naval shells, on skipping, had the exact opposite effect, they would fail to detonate at all.

lastly, the US 75mm AP round is at least 6 inches long? In other words, it more than likely did not pass through the 20 mm plate yet.

If a cylindrical HE vessel does not completely enter behind the penetration hole, the expansion of the explosive and and bulging of the shell case hinders penetration simply due to the fact that it is getting larger than the hole. Upon exploding, it reduces mass also further decreasing penetration.

Theres plenty of anectodal evidence that german AP rounds did fail to go off inside vehicles. Sherman crewmen report them lodged in bins, landing in peoples laps, etc.

[rexford]

Originally posted by Mr. Tittles:

And, yes, I did provide info that naval shells, on skipping, had the exact opposite effect, they would fail to detonate at all.

lastly, the US 75mm AP round is at least 6 inches long? In other words, it more than likely did not pass through the 20 mm plate yet.

If a cylindrical HE vessel does not completely enter behind the penetration hole, the expansion of the explosive and and bulging of the shell case hinders penetration simply due to the fact that it is getting larger than the hole. Upon exploding, it reduces mass also further decreasing penetration.

Theres plenty of anectodal evidence that german AP rounds did fail to go off inside vehicles. Sherman crewmen report them lodged in bins, landing in peoples laps, etc.

I guess you conveniently forgot about the 122mm APHE trials against spaced armor, which disproves your point. A 20mm plate isn't go to do much damage to a 122mm APHE round.

The 122mm APHE isn't go to bulge much due to a 20mm thick plate, so it was the contact that set off the HE burster and not some theoretical stuff about shell casings bulging and what have you.

Naval rounds skipping off water has nothing to do with WW II armor piercing anti-tank ammo.

Good bye on this thread.

[ June 29, 2004, 04:54 AM: Message edited by: rexford ]

[Mr. Tittles]

I would imagine the 122m APHE length is even longer than a 75mm APHE. In other words, its longer than 6 inches (the space between the plates) and therefore detonates OUTSIDE the 20mm plate. Did you catch that before or is everything needed to be repeated?

Its almost impossible to know if you have a point or if you think you are advancing an argument.

The 90mm predetonates way too early and the US 75mm and soviet 122mm detonate a little later but much too early also. Niether are german projectiles.

[ June 29, 2004, 12:00 AM: Message edited by: Mr. Tittles ]

[rexford]

Originally posted by Mr. Tittles:

I would imagine the 122m APHE length is even longer than a 75mm APHE. In other words, its longer than 6 inches (the space between the plates) and therefore detonates OUTSIDE the 20mm plate. Did you catch that before or is everything needed to be repeated?

Its almost impossible to know if you have a point or if you think you are advancing an argument.

The 90mm predetonates way too early and the US 75mm and soviet 122mm detonate a little later but much too early also. Niether are german projectiles.

The point which you overlook is that the impact with a 20mm plate was sufficient to set off the burster.

Another point which I raised which you did not acknowledge is that a plate thickness of 6mm is sufficient to set off the 88mm APCBC fuze. That thickness would not create or require much of a G force, would it?

Going through a 6mm plate sets off the burster. Seems extremely sensitive to me. Would ground impact be sufficient? Maybe yes, maybe no.

I suspect that the 6mm sensitivity of 88mm APCBC fuzes may have been designed to permit detonation of armor piercing rounds inside lightly armored armored cars and halftracks, and the rapid detonation of the 75mm Sherman APCBC round after partial penetration may have been a similar tactic to allow explosions inside German light armor.

I also suspect that large naval rounds required more of an impact than the 88mm (where a 6mm plate is required) to set off the burster, which explains why hits on destroyers would go completely through the ship without a detonation inside (minimum thickness for detonation and delayed detonation which would not be a problem against heavy armor). And why skipping off water might not be enough with a naval round.

I have also read of armor piercing penetrations of light armor where the round passed completely through the vehicle and detonated outside the car.

However, if early detonation of German APCBC bursters (before full penetration) were the general case than placing wheels, tracks and other relatively thin things on the front of a Sherman, with a short space to the main armor (6" or so), might be expected to defeat Tiger and King Tiger hits through detonation of the sensitive APCBC burster.

Did the Allies miss an important tactic which might have rendered the German Big Cat guns impotent?

It's possible that the 20mm spaced plate on PzKpfw III set off the burster because the hits were at 30 degrees or so which caused the round to jerk and change direction as it penetrated. The radical change in direction might have contributed to the projectile damage.

For Sherman 75mm and Russian 122mm armor piercing rounds with bursters to detonate against a spaced 20mm plate with a 6" spacing does suggest that the round detonated prior to full penetration. But note that in both cases the detonation of the burster was sufficient to cause defeat of the hit by damage to the projectile. The 50mm main armor was able to defeat the fragments.

You're both right (detonation of Sherman 75mm APCBC and Russian APHE occurs with less than full penetration) and wrong (HE burster is incapable of severely damaging the projectile and leading to defeat, 75mm APCBC had pre-detonation problems and various other subjects).

Looking back at the original issue which started all of this, an 88 hit next to a Sherman that supposedly rocked the tank, it seems most likely that the round was HE as you originally theorized.

I would also note:

The 90mm APCBC detonation on the armor surface in the tests before penetration was a flaw which was corrected, and Sherman 75mm and Russian 122mm AP detonation prior to complete passage through armor may have been a design tactic. Or it may have been a production or design problem.

The British use of armor piercing rounds without bursters, and the removal of the burster in U.S. 75mm APCBC ammo, may have been based on spaced armor considerations. And the Brits and Russians acknowledged that a 6" space was sufficient to set off bursters and defeat hits.

If you would be more open to other folks' comments it would help.

[ June 29, 2004, 04:55 AM: Message edited by: rexford ]

[rexford]

With regard to my previous message, British tests with German 75mm and 88mm APCBC showed that the burster would be damaged and fail to work properly on 45 through 55 degree hits. This may explain why Shermans and T34's would not be 100% protected by added spaced junk, the German bursters did not always work.

[Bastables]

Keep digging that hole Tittles/lewis

[Mr. Tittles]

Originally posted by rexford:

With regard to my previous message, British tests with German 75mm and 88mm APCBC showed that the burster would be damaged and fail to work properly on 45 through 55 degree hits. This may explain why Shermans and T34's would not be 100% protected by added spaced junk, the German bursters did not always work.

The german bursters were also smaller and even IF they were initiated AND detonated outside the armored envelope, they would not have as big an impact on the AP penetrater as a large cavity APHE would.

Again I will repeat that the timing of the burster is crucial. Being late (or just failing) is much better than being early or way too soon.

Naval shells would fail on skipping due to the base fuze pin getting misaligned by the sudden change in direction (the opposite of an early detonation, as I said earlier, they would fail). If this were the case with APHE shells for AFV, skipping off the ground or penetrating sloped armor would also exhibit this failure also. When penetrating sloped armor, the AP will ricochet through the plate as it finds a path of least resistance. The Pantherfibel has quick action film shots that show this. German reports said that T34 were very hard to burn from the front (after they were penetrated). This could be from not only fuze failure but the AP being directed downward towards the forward floor.

[ June 29, 2004, 09:55 AM: Message edited by: Mr. Tittles ]

[Mr. Tittles]

You're both right (detonation of Sherman 75mm APCBC and Russian APHE occurs with less than full penetration) and wrong (HE burster is incapable of severely damaging the projectile and leading to defeat, 75mm APCBC had pre-detonation problems and various other subjects).

No I am right and you are changing your tune!

YOU are the one that claimed APHE went off like grenades. I am the one that said that small cavity HE would not damage the APHE that much.

In the case of the US 75mm APHE, what mechanisms do you imagine are taking place since you have already said that it WOULD pierce the two plates if it had an inert filling? The test1 on the website shows that an inert 75mm APHE will penetrate and the report attributes this to fuse failure (they say between the plates but the ass end of the 75mm APHE may actually be outside the 20mm plate when it actually detonates).

As an aside, it appears that 50mmFH+20mmHOMO is actually much better than 70mmHOMO by itself. This is in the case of inert and loaded APHE.

Also interesting:

3. Against 70mm homo plate at normal or 60mm and thinner plates at 30º the shell was as successful as shot and gave detonations at distances of up to 20 feet in rear of the target(5).

Here it seems that the fuze IS working. Hmmmmm. kind of shoots a hole in your theory about shocks from ricochets! The same 75mm APHE is being stressed by 70mm RHA and detonates up to 20 feet away! This is quite a long time actually. Logically greater than 10 millisecs!

[ June 29, 2004, 11:03 AM: Message edited by: Mr. Tittles ]

[Mr. Tittles]

http://www.geocities.com/desertfox1891/pantherfibel.htm

Heres the pantherfibel images go to pg. Wieviel knackt die PzGranate?

The one image showing a bounced round appears to imply that the armor bowed in but rebounds.

[ June 29, 2004, 11:13 AM: Message edited by: Mr. Tittles ]

[Mr. Tittles]

An anectode from Death Traps is that a Sherman is holed by a 75mm german round. The round is found within the vehicle interior, it is then used as a plug to repair the hole in the armor!

[Bastables]

Originally posted by Mr. Tittles:

You're both right (detonation of Sherman 75mm APCBC and Russian APHE occurs with less than full penetration) and wrong (HE burster is incapable of severely damaging the projectile and leading to defeat, 75mm APCBC had pre-detonation problems and various other subjects).

No I am right and you are changing your tune!

YOU are the one that claimed APHE went off like grenades. I am the one that said that small cavity HE would not damage the APHE that much.

I think you'll find that making up rexfords arguments and then attacking them in your own internal debate, does not make you "right".

[MikeyD]

An inquiry. I've never heard any report about the ability of the PzIV's soft metal side skirts to pre-detonate AP burster charges. Has anyone got any info on this? I suppose there's a difference between striking 8-12mm of soft steel and 20mm face-hardened plate. An AP round might pass through a skirt plate like it wasn't even there.

[Mr. Tittles]

Again, the important thing is not what starts the initiation of the fuze but how LONG the detonation train takes to set off the charge.

APHE have base fuzes that must have some 'delay' built in to the mechanism. Microsecomds would be WAY too quick and the minimum delay may actually be 5-15 milliseconds at least. If a 75mm APHE round went through 70mm of RHA and then another 20 feet, its on that scale of time.

Its starting to become apparent that in the case of the US 75mm APHE, there is enough data to conclude that the fuze failures were not because of the soft 20mm setting it off, but the face hardened 50mm plate coming into play. The cause of the failure is certainly not shatter gap or anything like that. The disproof of shatter gap is that inert rounds DID make it through. The fuze MAY be initiated by a soft 20mm plate (which WAS rexfords main argument about skipping rounds being set off) but the face hardened plate MIGHT be causing an instantaneous detonation through shock. In other words, he just reinforced my argument further.

The fuzes worked fine with RHA (up to 70mm). They failed with FH. Its starting to all come together.

[ June 29, 2004, 02:59 PM: Message edited by: Mr. Tittles ]

[John D Salt]

Originally posted by Mr. Tittles:

Theres a couple of earthly reasons to have a HE in the back of an AP shell. One is to have an explosive go off inside a confined space. Namely the interior of a AFV. It would be very dangerous (even if small HE) and if the hatches were closed, especially so. The AP round would also be reaccelerated by having the detonation take place in its rear. Any fragments blown off the end or having the fuze blow out the back would be gravy.

A german 75mmL48 has such a small cavity that it is less than a 1/3 of the diameter and most of this small space is occupied by the fuze! These are AP (read very hard) shells. I doubt that the small HE would do more than break the back of the AP shells rear into more than a few pieces.

It's not at all clear to me whether you believe that the burster in a 7.5cm PzGr 39 would fragment the shell. On the one hand, you seemed originally to say that it won't; now you're having it fragment. There is, of course, no mechanism by which the HE burster can do damage inside the vehicle without fragmenting the shell containing it, so I assume from the above that you accept that the bursting charge does, exactly as the name inplies and all sources I have ever seen agree, burst the shell.

All the best,

John.

[Mr. Tittles]

Depends by what you mean by burst. Of course it will explode and escape the vessel (cavity). It may 'burst' the part in the rear of the shell that has a cavity in it. But it would not be more than minimal pieces. In other words, it has no chance in hell of fragmenting the non-cavity part of the APHE shell. So if the APHE has a large cavity like the soviets, and it detonates before penetrating, it WILL lose much mass. A smaller cavity APHE round would not suffer as much.

There was a long HE thread that had many formulas and it may be worth looking up. The bottom line is that fuse is threaded in and the walls are very thick and strong. I would be very surprised if the fuse and one to three large pieces are generated (and at a low velocity also).

Again, any explosion within the confines of a tank would have abandonment effect at least. If you have some time this July 4th, get an M80 and climb into a dumpster and close the lid. Light M80. Get back to us with results.

In addition, any ripped open shell casings or fuel could be put alight by the explosive.

Note: US used Comp D in its APHE and the Germans used RDX(cyclonite). This may be a clue also.

[ June 29, 2004, 05:30 PM: Message edited by: Mr. Tittles ]

[Mr. Tittles]

http://panzertracts1.tripod.com/images/pztr4-1.jpg

interesting