Accuracy Data for 88mm Flak

[Rausch]

Lorrin,

I told the lateral and vertical dispersion as they are given in the original sources, but they could of course have mixed up the order in the sources themselves I have simply no data till now to make a final decision if they mixed up the order.

The diameter of the round at the driving bands was 90.7 mm for the 8.8 cm Pzgr. 39 and 91.7 mm for the 8.8 cm Pzgr. 39-1 (Al). The 8.8 cm Pzgr. 39-1 was only allowed to be fired out of the 8.8 cm Kw.K./Pak 41 if the barrel had not fired more than 500 shots. The final 39/43 had a diameter of 92 (perhaps 92.6, hard to read due to source quality) mm at the driving bands.

The difference between the 39-1 and the 39-1 Al types seems to have been, that the ballistic cap was made out of aluminium for the second variant. This way a hit could be better observed since on impact the cap produced a bright white flash.

I have never seen German data for a 95% hit area. The ballistic tables were always telling the 50% area and the additional data I have (not for this but other guns) is for a 100% hit area.

Regards,

Michael

[ September 09, 2004, 04:19 PM: Message edited by: Rausch ]

[Mr. Tittles]

Would like to see 100% if you have it.

[rexford]

Great info Michael!

Thanks so much.

Lorrin

[rexford]

Originally posted by Mr. Tittles:

Would like to see 100% if you have it.

100% dispersion data is not real in the sense that weird wild rounds can always be just a little further out if one goes from 1 million to 10 billion rounds.

The 90% zone for 17 pdr APCBC at 1000m is 1.19m high and 1.01m wide. The corresponding 68.26% zone dimensions are 0.73m vertical and 0.61m lateral.

The 50% zones for 17 pdr APCBC at 1000m would be 0.49m high and 0.41m sideways.

The 50% zones for 88L56 APCBC at 1000m are 0.4m and 0.2m.

Keep in mind that the German figures are averages, so many guns would be vastly superior and many would be really awful looking.

[rexford]

Michael,

Do you have the ballistic table for 88L56 Pzgr 39 fired at 800 m/s?

Would it be possible for you to post the flight time and velocity figures from 0 to 2000m in 200m intervals?

Or to e-mail me a copy of the scanned page?

Thanks.

Lorrin

[Mr. Tittles]

Actually I just read that German manufacturing of the guns led to very similar performance between guns of the same type. There would not be such a wide performance between guns of the same type as you claim. They had strict QC. There would be wear with use of course but I wonder haw many guns ever fired even 500 rounds. The ammo was probably more prone to variations than the guns.

German propellent was also unique. I read of a US tanker who was looking for things to burn to keep warm. He worked a AP round out of a 88mm and was surprised that the gunpowder was similar to uncooked spagetti. It would take off like a bottle rocket when lit on one end. Perhaps the German powder was easier to match the ammunition?

As far as 100% dispersion, I would be happy just to see a 10 round shot group. I would want to see the real data instead of the 50% data.

[ September 10, 2004, 04:56 PM: Message edited by: Mr. Tittles ]

[lorrin]

"Actually I just read that German manufacturing of the guns led to very similar performance between guns of the same type. There would not be such a wide performance between guns of the same type as you claim."

Michael did not claim anything, he quoted official statistics. If the data suggests that the Flak gun had a wider dispersion than the tank gun, there may well have been some good reasons that we are either not aware of or don't realize the importance.

"As far as 100% dispersion, I would be happy just to see a 10 round shot group. I would want to see the real data instead of the 50% data."

A 10 round shot group has the potential of including alot of extreme scattering or close scattering that is not representative of the true average.

50% zones are real data, you are looking for the individual data points.

The conversion of the 90% zone data for 17 pdr APCBC to 50% zone numbers shows that the German 50% zone figures are reasonable and realistic.

While you may continue to search for the holy grail (individual data points for German dispersion tests) I am finished discussing the issue. 50% zones are REAL DATA and are averages of many guns and many rounds by many different makers on many different days.

[Mr. Tittles]

Krupp, Essen (personnel evacuated to Kettwig)

Dr. Dihrberg said that specification required that 50 per cent of shots should fall within a 50 cm. square on a vertical target at 1000 metres range. Dispersion was checked for tank guns, with 10 round groups, at ranges varying from 500 to 3000 metres.

Jump varies slightly from gun to gun, but for range table purposes the results from a single gun are taken, since the variation is very slight. Droop is considered a constant for all guns to a given design.

[Mr. Tittles]

"Actually I just read that German manufacturing of the guns led to very similar performance between guns of the same type. There would not be such a wide performance between guns of the same type as you claim."

Michael did not claim anything, he quoted official statistics. If the data suggests that the Flak gun had a wider dispersion than the tank gun, there may well have been some good reasons that we are either not aware of or don't realize the importance.

Not sure what you are talking about. My point is that one 75mmL48 is very much similar to another 75mmL48. I am not making any comment about Michaels data. I am not saying a Tiger 88mm is like anything but a Tiger 88mm in performance. Its in rebuttal to your claim about such a wide difference in performance in guns of the same exact type.

[Rausch]

"Would like to see 100% if you have it."

Sorry, but the 100% data I have so far is for plane guns and so of no help on this matter.

"Do you have the ballistic table for 88L56 Pzgr 39 fired at 800 m/s?"

I have only the ballistic manual from 1944 and the table there is for sure for the 39-1. The "Geschoßblätter" only contains the penetration and dispersion data for some distances. I am sure there was a 1942/43 manual holding the data for the Pzgr. 39, but I couldn't find anyone till now.

"Actually I just read that German manufacturing of the guns led to very similar performance between guns of the same type. There would not be such a wide performance between guns of the same type as you claim."

As Lorrin wrote, these are no claims but citations of the original German charts I read in original at the BAMA Freiburg and obtained a copy to work with at home. The different dispersions could have a reason in the different recoil mechanism or loading chamber (or an unknown factor).

The mounting is unprobably the reason, since this would be the first German gun where different mountings resulted in different dispersions.

E.g. the 5 cm Pak 38 and 5 cm Kw.K. 39 had listed the same dispersion values, the 8.8 cm Kw.K. 43 and 43-1/-2/-3 had all different mountings but used the same ballistic manual, and also the 7.5 cm Kw.K. 40 and the 7.5 cm Pak 40 used again the same ballistic manual.

Regards,

Michael

[lorrin]

Originally posted by Rausch:

[QBE.g. the 5 cm Pak 38 and 5 cm Kw.K. 39 had listed the same dispersion values, the 8.8 cm Kw.K. 43 and 43-1/-2/-3 had all different mountings but used the same ballistic manual, and also the 7.5 cm Kw.K. 40 and the 7.5 cm Pak 40 used again the same ballistic manual.

Regards,

Michael [/QB]

Good point.

The 50mm L60 and 88mm L71 guns fired at the same velocity, while the 75L46 Pak 40 and 75L48 fired at different velocities.

The above statement suggests that the 75mm L46 Pak APCBC would have the same dispersion characteristics as the 75mm L48? The answer to that question would be very interesting.

[lorrin]

Originally posted by Mr. Tittles:

"

. My point is that one 75mmL48 is very much similar to another 75mmL48. I am not making any comment about Michaels data. I am not saying a Tiger 88mm is like anything but a Tiger 88mm in performance. Its in rebuttal to your claim about such a wide difference in performance in guns of the same exact type.

Couldn't make out at first what your point was about the same guns.

I think you forgot the Churchill trials and what they suggested.

The British firing tests with 6 pdr Churchills show that wide differences are possible in the performance of the 6 pdr guns in different tanks. Whatever the cause, the German data is an average and some will be higher, some will be lower.

Ditto for German APCBC penetration. Quality control tests show a 24% difference in the velocity needed to defeat a given plate, as measured from high to low.

The Churchill trials show some guns with about 50% of the average dispersion, others with almost 200% of the average.

I bet that rifles have unique characteristics if one goes from one to another. Some may pull more to the right, or tend to shoot high for the same aim, etc.

[Mr. Tittles]

I am speaking about the state of newly manufactured equipment. The Krupp, Essen (personnel evacuated to Kettwig) source states as much also.

If you have ever been involved in the manufacture of precision equipment, then you would know that the equipment must meet a specification and does so through proof testing.

The Churchill test may have mixed aged equipment and experience of gunners and levels of zeroing of equipment. You do not have the methodology on that test do you? I would take it as anectodal at best then.

[Mr. Tittles]

Rheinmetall-Borsig. Dusseldorf

Muller stated that the accuracy required of tank guns was laid down by the Heereswaffenamt, but neither he nor Zimmer could state from memory what the requirements were. The design department of Rheinmetall-Borsig was moved in 1943 from Dusseldorf to Leipzig, and due to air attack there, it was subsequently moved again to the suburbs of Leipzig. Ludwig, Hermann and Banck of this department may have some details on this matter of accuracy. All were possibly at Dillenburg, near Wetzlar. (Braun of Unterluss thought that Hermann and Banck were at Heidenheim).

Muller did not know the required tolerances between bore and shot. He considered that there was no gun to gun variation in jump (i.e. for a given design) provided the propellant charge was standard. Droop was disregarded, because tank guns were considered to be too short and stiff for droop to be important.

Here again we see a source stating that for a given design, there was little variation in jump. Notice the stipulation on propellent charge (like I said, the ammo had more variation than the gun potentially).

The spec comes from Heereswaffenamt and they would stipulate a testing procedure to accept manufactured weapons. It would be good to get these procedures.

[lorrin]

Mr. Tittles:

The Churchill trials reveal alot more than you referred to in your last posts, and you might wish to study the results more closely along with my analysis of the data.

6 pdr APCBC has a larger dispersion than the Tiger 88L56 APCBC, and one would expect that Churchill firing trials against a 2' x 5' target would result in a lower hit probability than the Tiger.

The three best Churchills had an average hit percentage HIGHER than the 88L56 at three of the ranges:

500 yards

89% for 3 best Churchills, 96% for Tiger

800 yards

84% for 3 best Churchills, 83% for Tiger (even though the difference is small, the expected difference should be reversed and much larger)

1000 yards

81% for 3 best Churchills, 75% for Tiger

1500 yards

62% for 3 best Churchills, 54% for Tiger

If the three best Churchills outperformed the Tiger at 800 yards through 1500 yards, it follows that the worst two Churchills would be expected to perform significantly worse than the average 6 pdr even if their crews and bore sighting were perfect.

There is a limit to how good one can make a weapon system using bore sighting, good crews, etc., and the best explanation for the three Churchills is better than average guns. And one would then expect less than average performance from below average guns.

With regard to the German expectations for accurate guns, the 75L48 APCBC clearly fails to meet the criteria as does the 88L56 APCBC if my calculations are correct.

[Mr. Tittles]

The Churchill trials reveal alot more than you referred to in your last posts, and you might wish to study the results more closely along with my analysis of the data.

And I certainly would IF you could provide the methodology and other details. I would tend to want that before analysis begins.

Its funny how you can poo-poo 5 shots from a Tiger tank that the British achieved, or downplay the firing of 10 rounds at a target (10 rounds WAS the german procedure by the way), but feel that this very strange Churchill shoot is a basis for German gun analysis.

Its a very strange way to report results if nothing else. 3 best guns? 2 worst guns? Why bot just present the data? Do you have any other info on this shoot?

There is a limit to how good one can make a weapon system using bore sighting, good crews, etc., and the best explanation for the three Churchills is better than average guns. And one would then expect less than average performance from below average guns.

So when a majority of tested items do better than expected, you feel the assumption is that they are outliers?

[Jeff Duquette]

Hi Rausch:

Great research. Hopefully this puts to rest the use of pzgr39 by both the KwK-36 and Flak-18/36. And that the pzgr39 was probably being employed as early as 1942 by Flak 18/36. It’s surprising that this is even a source of debate, as this information is readily available in a number of mass produced booklets such Osprey's study of the Flak 18/36, Piekalkiewicz’s study of the 88, as well as Jentz's Panzertracts booklet on the Flak 18/36.

I have several questions, but I haven’t been following the thread as closely as I should have, other than to review a couple of your last posts. Your posts caught my eye because of the extensive set of references actually being cited. You may have already answered my questions somewhere within this thread. If you have I apologize in advance for bombarding you with the questions again.

The dispersion values for Flak 18/36 when firing either pzgr or pzgr-39 look very uncharacteristic for armored piercing ammunition. Typically vertical dispersion is greater than deflection, and increases at a greater rate than lateral dispersion relative to range. We are seeing quite the opposite in the values you've posted. I know that your Flak-18/36 pzgr dispersion values have been reversed in their order (i.e. the Height values have been reversed from the width values). I am assuming that either you, or the original author of this data also revered or transposed the order of the Flak-18/36 pzgr-39 values? Any thoughts on this?

I want to make sure I am clear on one of your later points. The early Merkblatt for the Flak-18/36 clearly shows both the lighter pzgr round and the heavier pzgr-39 round being available at the time the manual was published (i.e. May 1942). You are indicating that pzgr-39 for Flak begins production in 1942, and that production appears to switch to Flak pzgr-39-1 in 1943. Is this correct? Do you know off hand what the 39-1 modification was?

In the reference section of your post you cite a 1944 schusstafeln for the KwK-36. I am assuming this implies that the dispersion values you have quoted are for pzgr-39-1(FES) and pzgr-39-A1(FES). You also cite a 1938 schusstafeln for Flak-18/36 which presumably is the source for dispersion on the Flak 18/36 when firing the lighter pzgr round. Which of the references that you cited detail the schusstafeln for Flak-18/36 firing the heavier pzgr-39 projectile, and is their similar information available for the Flak 18/36 when firing pzgr-39-1?

Thanks for yout time and consideration, and I look forward to reading your reply.

Best Regards

Jeff

Rausch Said:

Here are the values for a 50% dispersion zone. Format is distance - width x height (all in m).

8.8 cm Pzgr. fired from 8.8 cm Flak:

100 - ? x ?

500 - 0,3 x 0,2

1000 - 0,7 x 0,4

1500 - 1,1 x 0,6

2000 - 1,6 x 0,8

8.8 cm Pzgr. 39 fired from 8.8 cm Flak:

100 - 0,1 x 0,1

500 - 0,3 x 0,2

1000 - 0,5 x 0,7

1500 - 0,8 x 1,1

2000 - 1,0 x 1,6

8.8 cm Pzgr. 39 fired from 8.8 cm Kw.K. 36:

100 - 0,1 x 0,1

500 - 0,2 x 0,2

1000 - 0,2 x 0,4

1500 - 0,3 x 0,6

2000 - 0,5 x 0,9

---SNIP---Regarding amo production I have not seen till now a detailed breakdown of the 8.8 Pzgr. 39 rounds in the subvariants.

When I look on the anual ammo production summaries (which break the production numbers down to single months) I notice that the headers changed from "8,8 cm Pzgr." at the beginning, in 1942 to "8,8 cm Pzgr. u. 39" and again in 1943 to "8,8 cm Pzgr. 39 u. 39-1".

This is true for the Kw.K. and the Flak production numbers, so the Flak could and did

also fire the 39-1 variant. It looks to me that the 39-1 variant was introduced in 1943 while the 8.8 cm Pzgr production ceased in 1942, but the percentage of whole production was not pointed out. ---SNIP ---

Sources are:

1) Geschoßblätter von Wa.Prüf. Amt 1, no date, but regarding the ammo described late 1943 or 1944.

2) H.Dv. 119/328 – Schußtafel für die 8,8 cm Kampfwagenkanone 36 (L/56) (8,8 cm Kw.K. 36), Februar 1944.

3) H.Dv. 119/763, L.Dv. 500/763 – Erdschußtafel für die 8,8 cm Flak 18 mit 8,8 cm Sprgr. L/4,5 (Kz) mit Zt.Z. S/30 oder A.Z. 23/28 und 8,8 cm Pzgr. mit Bd.Z. der 8,8 cm Pzgr, September 1938, Nachdruck von April 1940.

4) H.Dv. 481/60 – Merkblatt für die Munition der 8,8 cm Kampfwagenkanone 36, 8.1.1943.

5) H.Dv. 481/541 – Merkblatt für die Munition der 8,8 cm Flugabwehrkanone 18 (8,8 cm Flak 18) und der der 8,8 cm Flugabwehrkanone 36 (8,8 cm Flak 36), 20.5.1942.

6) L.Dv. 4402/5 – Die Munition der Flakartillerie, Beschreibung, Teil 5, Munition der 8,8 cm Flak 18, 36 und 37, Juli 1942.

[ September 12, 2004, 09:00 AM: Message edited by: Jeff Duquette ]

[Jeff Duquette]

Never mind ... looks like most of my questions have already been asked and answered.

I think the only question left is what was the source of the Flak 18/36 dispersion data when firing pzgr.39? I didnt see a schusstafeln cite for this information. Is there similar data available for the 39-1?

[Rausch]

Lorrin, the ballistic manual tell that the rounds fired by the 7.5 cm Pak 40 and 7.5 cm Kw.K. 40 had the same muzzle velocities. The shorter barrel of the Pak was compensated by more propellant and a resulting higher gas pressure in the barrel.

Jeff, the source you are looking for is the No. 1 of my source list.

For the 39-1 I have the ballistic tables for the 8.8 cm Kw.K. 36 and the 8.8 cm Kw.K. 43. Missing is the table for the 8.8 cm Flak 41.

[lorrin]

Originally posted by Rausch:

Lorrin, the ballistic manual tell that the rounds fired by the 7.5 cm Pak 40 and 7.5 cm Kw.K. 40 had the same muzzle velocities. The shorter barrel of the Pak was compensated by more propellant and a resulting higher gas pressure in the barrel.

Jeff, the source you are looking for is the No. 1 of my source list.

For the 39-1 I have the ballistic tables for the 8.8 cm Kw.K. 36 and the 8.8 cm Kw.K. 43. Missing is the table for the 8.8 cm Flak 41.

The British list muzzle velocities of 792 m/s for the 75L46 Pak 40, and 750 m/s for the 75L48, firing APCBC.

[Rausch]

Lorrin,

the ballistic manual as well as the source No. 1 from my source list tell 750 m/s for both guns for the 7.5 cm Pzgr. 39.

Additional to that the muzzle velocities measured between 1942 and 1945 by Krupp during their penetration firing trials was for both guns between 750 and 770 m/s.

And finally also the data sheet collection of the OKH from January 1944 tells 750 m/s for both guns.

[lorrin]

Originally posted by Rausch:

Lorrin,

the ballistic manual as well as the source No. 1 from my source list tell 750 m/s for both guns for the 7.5 cm Pzgr. 39.

Additional to that the muzzle velocities measured between 1942 and 1945 by Krupp during their penetration firing trials was for both guns between 750 and 770 m/s.

And finally also the data sheet collection of the OKH from January 1944 tells 750 m/s for both guns.

I think you may have cleared up another area of confusion. I had been giving more credit to the British reports than the 7.5cm Pak 40 notation on the top of the German ballistic table that stated 7.5cm KwK 40, 7.5cm StuK 40 und 7.5cm Pak 40. Thought the reference to the Pak 40 was a typo.

Thanks again.

[Mr. Tittles]

This is news. Most sources state a higher velocity for the PAK40 weapons. The higher velocity for the shorter L46 weapon did always seem odd. But what about the penetration differences then?

I believe the sights are not the same?

There could be confusion about the pak39 (hetzer gun) and pak40 perhaps?

[lorrin]

Originally posted by Mr. Tittles:

This is news. Most sources state a higher velocity for the PAK40 weapons. The higher velocity for the shorter L46 weapon did always seem odd. But what about the penetration differences then?

I believe the sights are not the same?

There could be confusion about the pak39 (hetzer gun) and pak40 perhaps?

Good points. The German ballistic table for the Pzgr 39 has 750 m/s for both the KwK 40 and Pak 40. Could the British be wrong?

One of the British ordnance board penetration curves lists the 75L43 APCBC muzzle velocity at 2360 fps, which is way low, but they got the 75L48 right.

Could you list all the sources you know which have 792 m/s for the 75L46 Pak 40 muzzle velocity, it would help.

Lorrin

[Rausch]

The Krupp penetration trials show identical penetration values for both guns.

The 7.5 cm Kw.K. 40 was used with the TZF 5f.

The 7.5 cm Stu.K. 40 was used with the 37 Sf.ZF 1a and Rblf. 36.

The 7.5 cm Pak 40 was used with the ZF 3x8° and Aushilfsrichtmittel 38.

Michael