Max Hit Probability

[Jeff Duquette]

<BLOCKQUOTE>quote:</font><HR>Duke:

Aaaah! No!! I would not call the VIIth corps a Green unit in any shape or form! Do you know how much we trained just prior to shipping out? Let me put it to you this way...of my first 2 years in the Army, over 60% of that time was spent in the field! This is about 30% more than normal even for a line unit in Germany.<HR></BLOCKQUOTE>

Duke:

No offence was intended by my green comment…just the opposite in fact. I have a huge amount of respect for folks that are slogging about on field problems for weeks at a time. Training Training, Training, Training. This is why I said in an earlier post there is a huge difference between troops with no combat experience and poor training, and troops with no combat experience but extensive training.

My use of the word "green" was more a reference to combat experience, or no combat experience. It was not intended as an indication of the average Coalition GI's proficiency (be he British, American, French, Canadian, etc) at performing the job he was trained to do. I am only guessing but probably some folks in your unit (or even yourself) had seen service in Panama, Granada etc. But big American Armored formations (Brigade sized units or larger) haven't really seen combat (as units) since WWII. Korea and Vietnam had various armored battalion commitments, but for the most part these wars were fought by Infantry formations for obvious reasons. Anyway I am hoping to avoid a discussion on semantics…and you strike me as the kind of guy that won't hold any of my slips of the tongue against me forever

Regarding using the Abrahm's as a yard stick; IMHO this perfectly valid for establishing a ceiling on capabilities. We can certainly point to modern gunnery and say this is what we are capable of now, and WWII gunnery should be well below this mark. Kind of reverse engineering. For instance we can look at CAT scores and say, "surely a WWII accuracy model or engagement time will not match modern CAT scores." CAT scores are interesting to look at, especially when there is a smorgasbord of vehicle types competing…M1A1, Leo-2, M60A1. In my mind it is a way of keeping a discussion on WWII accuracy in perspective. A shot considered difficult by today's standards - what with LRF's, Stabilization, high powered optics etc, etc, should be considered quite monumental by WWII optics and accuracy standards. Besides it's interesting **** to talk about. Surely this thread aint about CM anymore. We're just talking here right?

Anyway, now that your computer is fired up again, I still hope to hear your perspective on my earlier questions.

[Paul Lakowski]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Iron Duke:

Damn California and its power crisis!!! I haven't been able to use my PC all weekend (and part of last week) and look how much I miss out!

<HR></BLOCKQUOTE>

Yes well if you just pay us the money that you owe it wouldn't be cut off all the time

Some one asked about BELL CURVE. It means a distribution of results around a statistical average. So theres no such thing as a single penetration Vs plate X at a given range. If you take 10 shots you'll get 10 different results , if you take the average of these results thats the 'ballistic limit'. If you graphed those results you'd find that [ if its a normal distribution as in penetration] 2/3 of all results should fall within +/- 7% of the 'average figure' calculated above. Further 90% of results should fall within 2x 7%, while all results should fall within 2.6 times 7%[called the 'standard deviation'].

This appears to apply to accuracy and range estimation as well as has been mentioned by Rexford above.

In Ogorkiewcz Tech Of Tanks he reports Standard deviations for ranging system as follows [ off the top of my brain]

25-30% [of range] Visual estimation

15-20% stadimetric

5-10% Ranging MG

10-20 x Sqrt of range in km.Steroscopic Range finder

10-20% @ 1km.

14-28% @ 2km.

17-35% @ 3km.

These turn out to be Standard Deviations.

[This message has been edited by Paul Lakowski (edited 01-22-2001).]

[Guest Big Time Software]

Jeff said:

<BLOCKQUOTE>quote:</font><HR>Regarding using the Abrahm's as a yard stick; IMHO this perfectly valid for establishing a ceiling on capabilities. We can certainly point to modern gunnery and say this is what we are capable of now, and WWII gunnery should be well below this mark.<HR></BLOCKQUOTE>

Totally agree. As you say, looking at what can be done today, in this regard, at least establishes some sort of boundary that (in theory) no WWII gunnery platform should be able to match. It should not, however, be used for direct comparisions because there are too many variables. I think that is what Charles meant.

Steve

[rexford]

The beaten zones for HE fire by 75L48 and 88L56 are significantly different at 500m, and a realistic scenario might have both tanks firing HE at a human wave attack on the Ostfront.

Level ground is make-believe, to a degree, but the basic principles hold. Arching fire has less chance of a major undershoot or overshoot for equal dispersion and range estimate, and is more dependable when it comes to corrections or bracketing. We've run computer runs on this, and it looks plausible.

75L24 carried a heavier load of explosive than U.S. 75mm HE fired by Sherman. 1.91# explosive for 75L24 HE, 1.47# for U.S. 75mm HE. 75L24 HE carries about 30% more explosive by weight.

75L24 carried more explosive than 75L70, 0.85 kg vs. 0.65 kg, so lower muzzle velocity 75L24 HE carries 30% more explosive than Panther HE.

A fellow named Dietz ran a series of articles on German ammo, and guess what, 75L48 HE has different amount of explosive compared to 75L70 and 75L24 HE. German 75mm HE did not all carry the same load.

Another case (in a long string) that supports the theory that low velocity is normally associated with more explosive power, and also gives one better accuracy against ground point targets.

75L24 was a superb close support weapon despite a round trajectory. Good combination of HE explosive power and a nice ballistic arch to the flight path.

[Jeff Duquette]

Steve:

Mais naturellement vous êtes Steve correct. Pour la récréation seulement est notre disscussion sur l'armure. Que ce soit l'armure moderne, ou l'armure antique… ne nous concerne pas. It is all interesting, and its all just for fun

[:USERNAME:]

<BLOCKQUOTE>quote:</font><HR>Originally posted by rexford:

75L24 carried a heavier load of explosive than U.S. 75mm HE fired by Sherman. 1.91# explosive for 75L24 HE, 1.47# for U.S. 75mm HE. 75L24 HE carries about 30% more explosive by weight.

75L24 carried more explosive than 75L70, 0.85 kg vs. 0.65 kg, so lower muzzle velocity 75L24 HE carries 30% more explosive than Panther HE.

A fellow named Dietz ran a series of articles on German ammo, and guess what, 75L48 HE has different amount of explosive compared to 75L70 and 75L24 HE. German 75mm HE did not all carry the same load.

<HR></BLOCKQUOTE>

http://ourworld.compuserve.com/homepages/willphelps/Specs-03.htm

I would ask that you check out the above website.

7.5 cm. Ammunition

Type

Bursting Charge

Charge Weight

Booster

Fuze

Color

Notes

Sprgr. 34

HE

60/40 Amatol

0.454 kg.

Zdlg. Np. 10

Kl. Az. 23umg

olive green

-

Sprgr. Kw. K. (34)

HE

60/40 Amatol

0.853 kg.

Zdlg. C/98

Kl. Az. 23

olive green

-

This is data taken from the website. It states that the 75L24, 75L48 and the 75L43 all fired the Sprgr. Kw. K. (34).

You are funny in that you prove that even the uber-sherman 75mm had the same HE as a panther. When is that long lived fallacy going to be addressed?

I would ask that you also site references. I also cant help but notice that you ignore the fact that the 75mmL24 was not that low a velocity when compared to a german 75mmL48. You really have it in your mind that the angular difference is that different?

Lewis

[This message has been edited by :USERNAME: (edited 01-22-2001).]

[Jeff Duquette]

This is actually data for pzgr39 88mL56.

[This message has been edited by Jeff Duquette (edited 01-27-2001).]

[rexford]

Lewis,

Posted my source, Dietz' articles from late 60's or early 70's.

Dietz indicated the following:

75L24 HE .853 kg 60/40 Amadol

75L70 HE .654 kg 60/40 Amadol

Based on weight of explosive it would seem that Panther HE is equivalent of Sherman 75mm TNT, but we are not sure that 60/40 Amadol is equal to U.S. TNT.

The basic issue regarding accuracy against ground point targets has still not been successfully disproved.

Basic summary:

Wargames should have two HE accuracies, one against ground point targets and one against vertical targets. And the accuracy against vertical targets would have to include tanks, since HE was fired in attempt to damage running gear.

Low velocity HE is more accurate against a wide range of ground point target types, and low velocity HE usually packs more wallop than higher velocity HE shells. General rule.

[rexford]

Lewis,

My source is Diehl's articles, mistakenly used Dietz.

Diehl's original articles stated that 75L24 used different HE than 75L70 and 75L48. Did that web site you were so kind to note make a mistake copying Diehl's information. Diehl seemed pretty clear in stating that German 75mm HE was not equal in all cases.

When I originally read Diehl's articles and studied them in depth about 10 years ago, it seemed logical that 75L24 HE would have more 60/40 Amadol than Panther 75.

Thank you for the web site address, the penetration data is consistent with our own DeMarre estimates from British test of Panther 75mm and U.S. 75mm.

Now, if you could find a site that discussed the relative ground point target accuracy of low and high velocity HE. Did 88L56 HE, fired at 810 m/s, have as much explosive as 75L24?

We await your response.

[:USERNAME:]

I have to be frank here. I cant follow your thoughts rexford (dont feel bad..I have no clue what bastables is posting about either).

What are you saying? You read an article 10 years ago and thats your source?

Please try this:

1. Compare the HE velocities of the german 75mmL24, 75mmL48 and US 75mm. Do you really think they are that different? What, if you would like to guess, is the descent angle at 800 meters for these weapons? Do you think they vary by 10 degrees? 20 degrees?

2. How is infantry a point target? I was in the military and it was common to have a 5 meter interval between men. A 10 man squad is actually a big target.

I will continue to post references that support my contention that the germans manufactured a common type of 75mm HE shell for the KWK type weapons. From a logistics standpoint it makes alot of sense. I also believe that these weapons used the delay (that was a variable setting) to attack targets like troops in the open with ricochet fire.

do a search here and you will find alot of this is covered.

Lewis

[Matthew_Ridgeway]

<BLOCKQUOTE>quote:</font><HR>User Said:

do a search here and you will find alot of this is covered.<HR></BLOCKQUOTE>

You keep asking that references be posted to support opposing arguments, yet you have ended several posts with “do a search” for your own (insert hand into ass) references. This makes a lot of sense.

<BLOCKQUOTE>quote:</font><HR>USE said: I was in the military and it was common to have a 5 meter interval between men. A 10 man squad is actually a big target.<HR></BLOCKQUOTE>

Salvation Army perhaps? You guys spread out when picking up old bags of cloths from street corners? You never know when a hostile cat is gonna go for your ankles. “Cover me Lewis…I goin’ in for that bag of old underwear”.

<BLOCKQUOTE>quote:</font><HR>USE said: I have to be frank here. I cant follow your thoughts rexford (dont feel bad..I have no clue what bastables is posting about either).<HR></BLOCKQUOTE>

As obtuse as your train of thought seems to be, and your continued divergence from the topic of this thread, its very difficult for me to follow what your point is. But don’t feel bad; I suspect no one here has a clue as to what your babeling on about either.

<BLOCKQUOTE>quote:</font><HR>USER SAID: Did you know that shooting exactly at a monkey as it leaps off a cliff guarantees a hit? Fascinating but true!<HR></BLOCKQUOTE>

Did you know that if you jab a stick at a caged gorilla he’s likely to pick up his own feces and throw it at you. OK, I wanna know who jabbed a stick into USERNAME’s cage.

I came across a recent little gem from poor ol' USeRNAME. He’s apparently been slighted in the past by BTS (gee I wonder why)

<BLOCKQUOTE>quote:</font><HR>Guess Who Said This: I would think that BTS would agree that HEAT, HVAP and APDS (from a rifled 1940's gun) would be less accurate than a solid steel shot.

Then again you never know what revisionist thinking will get you.

I wrote up this big long post to stick on the end of the 88L56 optics thread but stopped and asked myself "what the f**K for?" Is it worth it when you are dealing with people that get the final word and can decide when an abstraction is needed and when an anal retentive stance is the only option and will argue down to the millimeter about AP rounds but futz up something like spotting (that throws off everything) and wont listen to any game changes like counter abstractions because they didn’t think of them and act like you are showing them some big hunk of wiped-bad doody paper?

It aint worth it. I get better things to do. I work with a-holes and dont need to come home to a hobby thats annoying. I get this crap at work, thanks, and this heres miller time boys.

Lewis<HR></BLOCKQUOTE>

I can really feel the emotion in that one USER. Tears must have been welling in your eyes as you wrote it. Get over yourself, or get a clue and go code your own frickin’ computer wargame. You can put all the “big hunks of wiped-bad doody paper” in it you want.

[This message has been edited by Matthew_Ridgeway (edited 01-23-2001).]

[rexford]

Lewis,

1. If I read an article 10 years ago would I have been able to give the HE weights to two or three decimal places. If you read thru all my recent posts it is obvious that we reread Diehl in reponse to your question.

2. Right now, Phelps' site may contain a typo regarding HE used by German 75mm guns, and we are looking to see if that is the case. Our reading of Diehl is that 75L24 packed more explosives than 75L70. We have the original Diehl articles, Phelps uses Diehl if you would read his references. Typo's sometimes occur when data is transferred.

3. Our comparisons have been between 75L70 and 75L24 HE, where there is a major difference in velocity. Your statement that 75L40, 75L48 and 75L24 HE is not that different in velocity, and we are therefore way off base, is just another attempt to cloud the issue.

We said that 75L24 was very accurate against ground point targets and had more HE explosive than 75L70, and 75L40 HE was more accurate than U.S. 76mm HE and had more explosives.

4. A bunch of men in an open field is a ground point target, one tries to put HE in the middle or close to it. Curving trajectories are better at walking in rounds till they land where one wants, due to a smaller change in ground location per change in gun elevation. Are low velocity howitzers or high velocity guns better at short range HE fire against ground points?

All the data we have seen points to low velocity.

Our earlier posts pointed to 810 m/s 88L56 HE and 750 m/s 75L70 HE.

I don't think that you understand this and all the explanations in the world won't help.

We have German ballistic tables, computer analyse's and pretty good logic on our side.

Where is your mathematical analysis? We have the original Diehl articles, you have a web site based on Diehl.

If you carefully read our previous posts on German HE explosive weight you would see that we have the Diehl article and used it, and ten years ago when we read Diehl we were left with an opinion regarding 75L24 HE that recent re-reeading supported.

The points you have brought up proved to be valuable and lead us to some good sites, and we appreciate your assistance. Most questions help open doors, and suggest new research paths.

We cannot, however, continue to correct your misstatements and distortions since we have a booklet on armor penetration to finish. If your make a substantive statement we will respond, and we are going to follow-up on German 75mm HE. Otherwise, we have said all that we are going to in response to your posts and await your analysis of HE trajectories (specifically 88L56 and 75L70 HE vs. 75L24 HE).

You disagree, we made our case, case closed until new evidence is provided.

[rexford]

We looked into what Gaussian bell shaped accuracy curve means, and how it stacks up against other analysis.

Assume 4.5% accuracy at 2000m on first shot for 88L71 APCBC, target is stationary and in full sight.

So 2000m equals about 2.00 standard deviations, 1 standard deviation is approximately 1000m.

92% at 100m

80% at 250m

62% at 500m

32% at 1000m

13% at 1500m

4.5% at 2000m

62% accuracy at 500m seems low for 88L71 APCBC, and may account for all the misses we have been seeing. With average 25% range estimation error (individual errors follow a bell-shaped curve and vary from 0% to over 75%),the hit probability may be closer to 90% to 95% at 500m for 88L71.

5% at 5000m

If 88L71 attains 43% "eighth shot" accuracy at 2000m after closing the range with bracketing, standard deviation is 2532m, so:

97% at 100m

92% at 250m

84% at 500m

69% at 1000m

55% at 1500m

43% at 2000m

32% at 2500m

23% at 3000m

17% at 3500m

11% at 4000m

The above results seem okay for wargaming, we would hold max hit % on any shot to 90% for realism sake (no one is free from mistakes and silly blunders all the time).

84% at 500m will allow for alot of factors that cause theoretical rate of fire and individual shot accuracy to lag behind training field exercises (hard to find or lift ammo reserves, jammed guns or fingers, confusing commands, sweat in eyes, etc.).

If max accuracy at 2000m against a stationary fully exposed target is 10% after eight shots, this seems a bit too conservative.

[:USERNAME:]

I cant believe it. Rex you are a classic. Good luck with you-alls article.

Heres a nice paragraph from The German Sturmgeschutze in WWII:

"The barrel of the 7.5cm assault cannon (StuG7.5cm-K) was 1307.5 mm long (=L24); the entire weapon weighed490 Kg, had a traverse of 24 degrees and a elevation field between minus 10 and and plus twenty degrees. At first the Panoramic Telescope 32 for StuG (4 x 10 degrees) was used as an aiming device. The gun fired ammunition that had been introduced for the almost identical Panzer IV. This was primarily the 7.5 cm shell which carried a 5.74 Kg charge up to 1000 meters at a very low height, and at an elevation of 20 degrees reached targets at a distance of 6200 meters (flight time 23.5 seconds)."

So Rex just ignore my points and go on "correcting" people. The fact is you continuely hammer in this point about curvy trajectorys and wont define what that is. Can you give us an angle? No. Do you know how to use the physical equations to figure that out from velocitys? I would guess not.

So good luck.

Lewis

[Matthew_Ridgeway]

USER Said: Heres a nice paragraph from The German Sturmgeschutze in WWII:

Most people who are getting anal about posting references (like yourself) will include an authors name. Perhaps you mean:

German Sturmgeschutze in WWII: Photo Chronicle

by Wolfgang Fleischer, Richard Eiermann

So let me get this straight your references include an internet site (with typos) and a Picture book on the Stug. Very impressive USeR.

[ASL Veteran]

Originally posted by :USERNAME::

The gun fired ammunition that had been introduced for the almost identical Panzer IV. This was primarily the 7.5 cm shell which carried a 5.74 Kg charge up to 1000 meters at a very low height, and at an elevation of 20 degrees reached targets at a distance of 6200 meters (flight time 23.5 seconds)."

Lewis

Ummmm Lewis, the Panzer IV originally had a low velocity 75 in it when it was first introduced. The longer 75 is a different gun than what was originally equipped on the Pz IV and I am sure that the passage you are quoting is in reference to the 'earlier' Panzer IV gun not the 'later' Panzer IV gun. The 1939 - 41 Panzer IV may have even been equipped with the 75L24 itself. I think your passage can be regarded as misleading and not placed in the correct context, unless you are not familiar with the history of the PzIV. By the way, if the weight of the HE in the shell is different, I'm not sure how they can be the same shell. Count me among the many who have no clue what your point is.

[Guest Big Time Software]

OK folks... let's settle down here.

Mathew_Ridgeway, although I share your observations on the quality of debate Lewis tends to display, I would appreciate you not sinking down to his level.

Lewis, can you PLEASE just stick to the point and stop bashing and ducking? It is really tiring and since NOBODY listens to you when you do this, it does your case no good. Hell, you could be 100% correct. But the way you present yourself it is hard to know if this is the case. Poor presentation + poor attitude = poor case.

Rexford, please don't pay Lewis more attention than he deserves. If he wishes to debate you in an acceptable way, that is one thing. But when he starts doing his temper tantrum stuff it is best, from my experience, to just ignore him.

As for your findings about explosive charges in these various rounds, we find this to be quite interesting. Currently we have all German 75mm Pak/KwK weapons using the same HE projectile in the game. This round is slightly better than the one used for US 76mm guns, but less effective than the ones used for US 75mm guns.

We are a bit dismayed that all the data on rounds we possess does NOT specifical include data for the 75mmL/24 High Explosive round. We have data for the various high velocity 75mm Pak/KwK guns, as well as data for various 75mm infantry guns. The interesting thing is that the projectiles for all are nearly identical. Therefore it is logical to assume that the L/24 is also the same. However... we have never been comfortable with this assumption.

You are saying that Diehl actually came up with the specific specs for the L/24 round? Great! Where did he get the data from and how can we get a hold of the article in question? We would love to see it and make changes to CM if we felt they were warrented from the data. We hate making decisions like this based on a small samples of data, but such is life

Steve

[Bastables]

User,

Ahh so you’ve contvinently forgotten our little debate about the StuG and its role/effectiveness. I argued that post 1943 the arming of the StuG with the high velocity StuK40 meant that they swapped out some of the effectiveness of a low velocity infantry killer StuK 37 in favour of changing the primary role of the StuG to tank killer. But I think you must have remembered the debate because you ‘argue’ so vehemently at the information that Rexford presents detailing why High velocity guns are poorer at killing Infantry relative to low velocity Howitzer type weapon. But then again you ignored my arguments by the statement that you did not understand my arguments either. Same old Lewis.

[Ben Galanti]

Ok, I just did some quick hand calculations (which means there probably totally wrong, so someone should check them...) to compare the 75L70 and the 75L24.

I used the following assumptions. Shell velocity was constant throughout flight (ignoring air resistance). Also, that impact was at the same level as firing, so just a simple parabola trajectory. Muzzle velocity for the 75L24 was 450 m/s and for the 75L70 was 925 m/s (please correct those if they are wrong also).

I found the impact angle (as well as the firing angle with the above assumptions) for hitting a spot on the ground 1000 m away. For the 75L24 its ~2.8 degrees, and for the 75L70 it's ~.7 degrees.

I also found the difference in range if the gun was .1 degree above and below the above stated angles (I don't know what kind of resolution could be achieved when setting the vertical angle of WWII guns, the .1 degree delta might not be appropriate.)

For the 75L70:

.6 degrees => 914 m

.8 degrees => 1219 m

spread of 305 m between angles of .6 and .8 degrees

For the 75L24:

2.7 degrees => 972 m

2.9 degrees => 1044 m

spread of 72 m between angles of 2.7 and 2.9 degrees

[This message has been edited by Ben Galanti (edited 01-23-2001).]

[PzKpfw 1]

Originally posted by Big Time Software:

You are saying that Diehl actually came up with the specific specs for the L/24 round? Great! Where did he get the data from and how can we get a hold of the article in question? We would love to see it and make changes to CM if we felt they were warrented from the data. We hate making decisions like this based on a small samples of data, but such is life

Steve

Steve et, all again; the below may provide some detailed answers to this & other things concerning German ammunition:

German Explosive Ordnance Projectiles & Projectile Fuses. March, 1953: NTIS call number ADA376695

Regards, John Waters

------------------

"We've got the finest tanks in the world. We just love to see the

German Royal Tiger come up on the field".

Lt.Gen. George S. Patton, Jr. February 1945.

[This message has been edited by PzKpfw 1 (edited 01-23-2001).]

[ASL Veteran]

Okay, since there seems to be some conflicting information on the actual guns themselves I figured I would post some data from “The Encyclopedia of Infantry Weapons of WW2” by Ian Hogg. These are not tank guns, but various guns used by infantry - AT and IG guns. Unfortunately all the data is in pounds and inches, but I’m sure the great minds on this board can convert this to metric if necessary.

7.5cm Leichte Infanterie Geschutz 18:

Barrel length: 35.43 inches

Breech mechanism: Shotgun, percussion firing

Projectile & Weight: HE, 13.2lbs

Propelling charge: Five-part; brass-coated steel case

Muzzle velocity: 690 ft per second

7.5cm Infanterie Geschutz 37:

Barrel length: 70.75in with muzzle brake

Breech mechanism: Vertical sliding block, semi automatic, percussion

Projectile & Weight: HE 13.2lbs

Propelling charge: Six part charge, separate loading, brass case

Muzzle Velocity: 918 ft per second

7.5cm Infanterie Geschutz 42 nA:

Barrel length: 70.75inches

Breech mechanism: Vertical sliding block, semi automatic, percussion

Projectile & Weight: HE, 13.2lbs

Propelling charge: Six part, separate loading, brass case

Muzzle velocity: 918ft per second

7.5cm Infanterie Kanone 290®:

Barrel length: 49.5inches

Breech mechanism: Interrupted screw, percussion firing

Projectile & Weight: HE, 13.75lb

Propelling charge: 18oz, fixed, brass case

Muzzle velocity: 1270ft per second

7.5cm Panzerabwehrkanone 40:

Barrel length: 145.75inches

Breech mechanism: Horizontal sliding block, semi automatic, percussion

Projectiles & Weight: AP 15lb; APCR 7.04lbs; HE 12.8lbs; HEAT 10.1lbs

Propelling charge: Steel case, lacquered. Fixed round

Muzzle velocity: AP 2600ft per second; APCR 3250 ft per second; HE 1800 ft per second

7.5cm Panzerabwehrkanone 41:

Barrel length: 170inches

Breech mechanism: Horizontal sliding block, semi automatic, percussion

Projectile & Weight: APCNR 5.72lbs

Propelling charge: 5.71lb, steel case, fixed round

Muzzle velocity: 3700ft per second

8cm Panzerabwehrwerfer 600 (also PAW 8H63):

Barrel length: 116.2inches

Breech mechanism: Vertical sliding block, electric firing

Projectile & Weight: HEAT 5.94lbs; HE 9.59lbs

Propelling charge: Steel spirally wrapped case with venturi plate

Muzzle velocity: HEAT 1700ft per second; HE 1375ft per second

8.8 cm PAK 43:

Barrel length: 260.225inches

Breech mechanism: Vertical sliding block, semi automatic, electric firing

Projectile & Weight: AP 22.9lb; APCR 16lb; HE 20.3lb

Propelling charge: Lacquered steel case, fixed round

Muzzle velocity: AP 3282ft per second; APCR 3710ft per second; HE 20.3lb

[rexford]

75L70 fired HE at 750 m/s, 75L24 HE at 450 m/s.

75L70 HE took 1.2 seconds to reach 800m with 10 mil gun elevation, or 0.573° gun rise.

This is from German ballistic data that we have.

75L24 (estimated from 75L48 HE ballistic data starting with 450 m/s at 1075m and going to 390 m/s at 1875m) takes about 1.905 seconds to go 800m.

Using our simplified trajectory equations, descent angles at 800m are 9.49 mils for 75L70 HE and 23.0 mils for 75L24. In terms of degrees this equates to 0.544° for 75L70 and 1.318° for 75L24.

If dispersion drives trajectory up by 1m at 800m (German data shows that 50% of 75mm L48 HE shots will have vertical dispersion of at least 1m at 800):

75L70 HE is off by 105m on shot at 800m when range estimate is perfect and vertical dispersion is 1m

75L24 HE is off by 43m on same shot as 75L70 HE.

How many HE shots will be within 20m of target when range estimate is perfect and 50% of vertical dispersion exceeds 1m?

--------------------------------------------

10% of 75L70 HE shots will be within 20m of target with a perfect range estimate at 800m.

24% of 75L24 HE shots will be within 20m of target with a perfect range estimate at 800m.

--------------------------------------------

There it is, trajectory analysis that fully supports what my posts have been saying, 75L24 HE is very accurate due to low velocity and arching trajectory, and "if" 75L24 HE round has more explosive then other German ammo (and I am getting the Diehl pages on this), then 75L24 is even more lethal.

[rexford]

The simplified trajectory equations are based on rounds over 2000 fps, so offer rough estimates for slow stuff like 75L24.

Will do more exact analysis in next hour and post it.

[rexford]

Did a more accurate trajectory analysis.

Ground point target at 800m, range estimate is 800m. 75L24 HE fired at 450 m/s, 75L70 HE fired at 700 m/s.

75L24 HE trajectory has firing angle of 1.281° and final descent angle of about 1.429°. 1.905 seconds to 800m.

75L70 HE trajectory has firing angle of 0.507° and final descent angle of about 0.564°. 1.200 seconds to 800m.

If vertical dispersion is 1.0m, 75L24 is off by 40m and 75L70 is off by 102m on flat ground. Higher percentage of 75L24 HE shots land close enough to target to do something useful.

What happens when 88L56 tries to hit a ground point target with 810 m/s HE? Would you rather have 75L24 or 88L56 against a ground point target?

[:USERNAME:]

Originally posted by ASL Veteran:

Ummmm Lewis, the Panzer IV originally had a low velocity 75 in it when it was first introduced. The longer 75 is a different gun than what was originally equipped on the Pz IV and I am sure that the passage you are quoting is in reference to the 'earlier' Panzer IV gun not the 'later' Panzer IV gun. The 1939 - 41 Panzer IV may have even been equipped with the 75L24 itself. I think your passage can be regarded as misleading and not placed in the correct context, unless you are not familiar with the history of the PzIV. By the way, if the weight of the HE in the shell is different, I'm not sure how they can be the same shell. Count me among the many who have no clue what your point is.

I have no clue as to what you think you are talking about. I am posting this with the full knowledge that the author (its an OK book BTW) IS refering to the PIV with the L24. He is refering to the L24 stug also. He is describing the L24 weapons performance. The book is about Stugs? Anyone home?

The REASON I posted it is because he references the low angle of fire a weapon of this velocity would have. What you think I posted it for is the mystery. So do you get it? I am sorry but I cant draw pictures here.

Count me amongst the people who think you need to improve your reading comprehension skills.