RE: German 75mmL43, L48 and L46 velocities (Full Version)

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Elron Hubbub -> RE: German 75mmL43, L48 and L46 velocities (7/21/2016 6:23:37 PM)

After reviewing this thread, I think there may be some interesting information regarding the 8,8 cm Tigr I and FlaK 18/36 weapons as far as powder weights also!

You find the April 1944 German document yet Mobius? It really has some great stuff in it. You said you wanted 1944 data didn't you? Use your Google-Foo...



Mobius -> RE: German 75mmL43, L48 and L46 velocities (7/21/2016 6:42:21 PM)

quote:

ORIGINAL: Elron Hubbub
You find the April 1944 German document yet Mobius? It really has some great stuff in it. You said you wanted 1944 data didn't you? Use your Google-Foo...
I don't know what document you are talking about or what to google for?



Elron Hubbub -> RE: German 75mmL43, L48 and L46 velocities (7/21/2016 7:29:07 PM)

Merkblatt 28/1

It was right under your nose...

When I go to a website, and they actually cite sources (hint hint panzerWorld), I will cut and paste them into Google and see if they are now online. I actually wish there was a way to save searches and have them run once a month. You would be surprised how things pop up as time goes on...

I must say it is remarkable that there is so much info now compared to the early "hey-daze" of the Combat Mission forums.

Anyway, I would rate this investigative thread among the best.



Elron Hubbub -> RE: German 75mmL43, L48 and L46 velocities (7/21/2016 7:39:29 PM)

In any case, It seems that the Tiger I/Flak 16/18 may have had a progressive increase (not decrease) in powder weights for their armor piercing ammunition. Or, some of the documentation seems to reflect that.

Also, the much quoted "L56" barrel length may in fact be 'shorter'.

Edit: I will start a new thread for this 88mm conundrum



Elron Hubbub -> RE: German 75mmL43, L48 and L46 velocities (7/21/2016 11:57:44 PM)

http://codebuch.jimdo.com/downloads/



Mobius -> RE: German 75mmL43, L48 and L46 velocities (7/22/2016 2:39:14 AM)

I'm back looking for firing tables.
I did find a Soviet table that seems to have more accurate ballistics info than I currently have.
I does check out to within 2% when compared to German data


[image]local://upfiles/21308/C61AF006C44548E890B4583373A601BE.jpg[/image]



Elron Hubbub -> RE: German 75mmL43, L48 and L46 velocities (7/22/2016 3:26:21 AM)

Looks like copied German data too. Is that for a 37mm weapon?

In any case, i think this thread has wrapped up. If ANYONE can find ANY information regarding ANYONE reducing the German propellant for the PAK 40 (besides Fur Tropen) Pzgr 39 ammunition, THEN ...PLEASE...ANYONE please post that here....



Mobius -> RE: German 75mmL43, L48 and L46 velocities (7/22/2016 12:42:29 PM)

Yeah 37mm. No table of this in German nor found by Rexford is anywhere. It seems like I find something else from that what I'm looking for.

OK, close this up until something new on the 75mm/L46 is uncovered.

I guess Panzerworld just presents the archives they find rather than corrects the data.
Side by side of the same pzgr 39 shell.
[image]local://upfiles/21308/0DDC8D5057C74748AE10CBBDD4289B7C.jpg[/image]



Elron Hubbub -> RE: German 75mmL43, L48 and L46 velocities (7/22/2016 6:15:02 PM)

Since you like those transcribed data sheets so much....

https://www.scribd.com/doc/230234125/Dokumentation-W-127-Datenblatter-fur-Heeres-Waffen-Fahrzeuge-Gerat



Elron Hubbub -> RE: German 75mmL43, L48 and L46 velocities (7/22/2016 6:23:27 PM)


quote:

ORIGINAL: Mobius

This is worth posting.
Though the 1500m value of the Pak 40 pzgr39 is probably an error.


[image]local://upfiles/21308/F1B248B0EE0C48F5860F4438ECAB7269.jpg[/image]

Yes, there is also an error in the projectile weight for Pzgr 39, it should be 6.80, of course.

Is that from a report or do you know the document origin? I would expect the Pak 39 (r) to be in that report. It was certainly widely used in 1942? I have the data for it somewhere as far as accuracy and penetration.

H.Dv. 119/327 edition dated October 1944:
7.62 cm PzGr 39 rot of 7.6 Kg and 710 m/s MV with velocities at range and official 30 degree deflection performance figures.

100 meters 699 m/s 96 mm pen.
300 meters 678 m/s 92 mm pen.
500 meters 658 m/s 89 mm pen.
1000 meters 607 m/s 80 mm pen.
1500 meters 559 m/s 71 mm pen.
2000 meters 514 m/s 63 mm pen.
2500 meters 472 m/s 55 mm pen.
3000 meters 433 m/s 48 mm pen.
Treffer % firing at 2.5/2 meter target with 50% St. breite/hohe:
100 m 100(100)% .1/.1,
300 m 100(100)% .2/.2,
500 m 100(92)% .3/.4,
1000 m 90(52)% .6/.8,
1500 m 66(25)% 1.0/1.3,
2000 m 42(12)% 1.4/1.8,
2500 m 26(07)% 1.9/2.5,
3000 meters 17(05)% 2.4/3.3.



Mobius -> RE: German 75mmL43, L48 and L46 velocities (7/22/2016 10:26:15 PM)

quote:

ORIGINAL: Elron Hubbub

H.Dv. 119/327 edition dated October 1944:
7.62 cm PzGr 39 rot of 7.6 Kg and 710 m/s MV with velocities at range and official 30 degree deflection performance figures.

100 meters 699 m/s 96 mm pen.
300 meters 678 m/s 92 mm pen.
500 meters 658 m/s 89 mm pen.
1000 meters 607 m/s 80 mm pen.
1500 meters 559 m/s 71 mm pen.
2000 meters 514 m/s 63 mm pen.
2500 meters 472 m/s 55 mm pen.
3000 meters 433 m/s 48 mm pen.
Treffer % firing at 2.5/2 meter target with 50% St. breite/hohe:
100 m 100(100)% .1/.1,
300 m 100(100)% .2/.2,
500 m 100(92)% .3/.4,
1000 m 90(52)% .6/.8,
1500 m 66(25)% 1.0/1.3,
2000 m 42(12)% 1.4/1.8,
2500 m 26(07)% 1.9/2.5,
3000 meters 17(05)% 2.4/3.3.

Good find. The gun is not as accurate as I thought.



Elron Hubbub -> RE: German 75mmL43, L48 and L46 velocities (7/23/2016 12:08:19 AM)

I believe that there are two weapons that are converted Soviet weapons. That data is probably for the 7,62 cm F.K. 39.

Both the 7,62 cm F.K. 39 and Pak 39 (r) fired the same German ammunition which featured the German Pak 40 cartridge case. I see from the ammunition Merkblatt that the powder weight was initially 2.6 KG but the 1944 data shows it as lower at 2.45 KG. Perhaps to reflect the less robust 7,62 cm F.K. 39?

Most documents state the MV of the Pak 39 (r) as 740 M/s.

Edit: It appears that this is the 7,62 cm Pak 36 but firing the later round that had a reduced charge. Initially, this weapon had 2.6 Kg powder weight, but evidently it was reduced to 2.45 Kg.

Note that the correct name for the weapon is 7,62 cm Pak 36 without the (r). I suppose that once the Germans modified it and machined it, they also made completely German ammunition for it and therefore they 'owned' it.



Mobius -> RE: German 75mmL43, L48 and L46 velocities (7/23/2016 2:51:09 AM)

quote:

ORIGINAL: Elron Hubbub
Both the 7,62 cm F.K. 39 and Pak 39 (r) fired the same German ammunition which featured the German Pak 40 cartridge case. I see from the ammunition Merkblatt that the powder weight was initially 2.6 KG but the 1944 data shows it as lower at 2.45 KG. Perhaps to reflect the less robust 7,62 cm F.K. 39?
US source on captured 7,62 cm F.K. 296 (r) says it fired the original Russian shells. Chamber capacity was increased, muzzle break added and then used German ammo to be the 76.2mm PaK 36. US measured Vo at 706 m/s.



Elron Hubbub -> RE: German 75mmL43, L48 and L46 velocities (7/23/2016 11:08:04 PM)

This pic shows the two weapons. The long barreled weapon on top is the full German adaption of the 'F-22' Soviet 76.2 mm 'divisional gun'. The middle weapon is the common replacement for the F-22 that the Germans modified (76-mm divisional gun M1939 (F-22 USV or USV)). I am not sure if the Germans captured many ZIS-3 weapons and converted those. ZIS-3 'replaced' both Soviet weapons.

[image]http://www.lonesentry.com/german_antitank/pics/xgerman_antitank7_captured_pak.jpg[/image]

The bottom gun is the French Pak 97/38.

The Germans used Soviet weapons in 'as-is' form and had a designation for that (i.e. 7,62 cm F.K. 296 (r)) and, of course, used Soviet ammunition. They also did conversions and the F-22 conversion was fairly good with the Soviets even using 'back-captured' specimens (with German ammunition). The Marder series used the 7,62cm Pak 36 (r) also which is the F-22 conversion. This had a Pzgr 39 style projectile and used the Pak 40 cartridge case. The ammunition information is available online.

The 4/1944 ammunition document shows that the "Pak 36 u FK 39" (Pk 36 (r) and Field Kanone 39) share ammunition. I suppose that means that the Germans modified both these weapons to accept the German designed ammunition. I take FK 39 to be the middle weapon in the picture.



Elron Hubbub -> RE: German 75mmL43, L48 and L46 velocities (8/23/2016 10:39:41 PM)

Some interesting British data from Miles Krofus...

quote:

by Miles Krogfus » 21 Aug 2016 19:44

I list British Ordnance Board penetration graphs from 1943 and 1944.

O.B./43/CV.12 May 25,1943
shows for 2400 f/s muzzle velocity (731.52 m/s) of 14.81 lb. APCBC shell ("MV as tested by trial in KwK 40") at 0 and 30 degrees deflection:
2400 f/s penetration 121/102 mm,
2000 f/s (609.6 m/s) 98/83 mm,
1600 f/s (487.68 m/s) 75/63 mm.

O.B./43/CV.13 same date.
MV 1350 f/s (411.48 m/s) same shell model:
1300 f/s (396.24 m/s) 58/48.5 mm,
1000 f/s (304.6 m/s) 41.8/34.8 mm.

O.B./43/CV.20 for 15 lb. large HE cavity APCBC
1300 f/s MV December 14,1943:
1300 f/s 50.3/46.25 mm,
1000 f/s 35/32.94 mm.

O.B./44/CV.50 for 15 lb. small HE cavity APCBC December 13,1944 of Kwk 42
MV 3068 f/s (935.13 m/s),
Pak 40 MV 2600 f/s (792.48 m/s),
KwK 40 MV 2300 f/s (701.04 m/s):
3000 f/s (914.4 m/s) 182/156 mm,
2400 f/s (731.52 m/s) 133/104.5 mm,
2000 f/s (609.6 m/s) 104/77.5 mm,
1600 f/s (487.68 m/s) 75.5/55.5 mm.


I am assuming that the KWK 40 they tested is the L43 version.



Elron Hubbub -> RE: German 75mmL43, L48 and L46 velocities (8/25/2016 3:01:21 PM)

A nice tidbit by Miles Krogfus...

quote:

A 1942 welded small HE cavity 75 mm APCBC for the Pak 40 examined in the United States had a projectile weight of 14.65 lb (6.645 kg) and a propellant charge of 2.610 kg bagged on October 7,1942. Marked "Fur Tropen P.T.+ 25 (degrees) C."



Mobius -> RE: German 75mmL43, L48 and L46 velocities (8/25/2016 4:43:30 PM)

quote:

2400 f/s penetration 121/102 mm,
2000 f/s (609.6 m/s) 98/83 mm,
1600 f/s (487.68 m/s) 75/63 mm.

Are there any ranges associated with these Vz?



Elron Hubbub -> RE: German 75mmL43, L48 and L46 velocities (8/25/2016 11:37:03 PM)

I believe it is similar to some German graphs...that is, it is really 7,5 cm Pzgr 39 'across the board', meaning it is gun independant. That is, all weapons get this penetration IF they have the velocity.

The KWK 40 must be a L43 and might even have 'Fur Tropen' ammo being shot in a cold/dreary English base. Its too low.

I also assume British test armor



Mobius -> RE: German 75mmL43, L48 and L46 velocities (8/26/2016 1:19:31 AM)


quote:

ORIGINAL: Elron Hubbub

I believe it is similar to some German graphs...that is, it is really 7,5 cm Pzgr 39 'across the board', meaning it is gun independant. That is, all weapons get this penetration IF they have the velocity.

The KWK 40 must be a L43 and might even have 'Fur Tropen' ammo being shot in a cold/dreary English base. Its too low.

I also assume British test armor

I was hoping for more data points on the ballistic coefficient.
Using what I already know MV=2600 f/s - Term vel. 2000 f/s is 1200 yds; 1600 f/s is 2600 yds. @ 10ft elevation.



Mobius -> RE: German 75mmL43, L48 and L46 velocities (8/26/2016 1:56:04 PM)


quote:

ORIGINAL: Elron Hubbub

A nice tidbit by Miles Krogfus...

quote:

A 1942 welded small HE cavity 75 mm APCBC for the Pak 40 examined in the United States had a projectile weight of 14.65 lb (6.645 kg) and a propellant charge of 2.610 kg bagged on October 7,1942. Marked "Fur Tropen P.T.+ 25 (degrees) C."



quote:

O.B./43/CV.20 for 15 lb. large HE cavity APCBC
1300 f/s MV December 14,1943:
1300 f/s 50.3/46.25 mm,
1000 f/s 35/32.94 mm.

This is higher MV than the German data for the same 75mm/L24. And the penetration doesn't fall off nearly as fast as other sources indicate. Maybe the desert air lets the round fly better?



Elron Hubbub -> RE: German 75mmL43, L48 and L46 velocities (8/26/2016 10:58:03 PM)

My guess would be that they are testing in the desert, and the Germans may not have made a 'Fur Tropen' round for the short gun. The reason being the gun could take it. Look at its HE round, it has a higher muzzle velocity than the AP.

I guess the Germans put 7,5 cm Pzgr 39 on the short gun's ammo also?

I know at altitude, things fly better (thin air). I am not so sure about the low level desert air. I would assume they are using British test plate?



Mobius -> RE: German 75mmL43, L48 and L46 velocities (8/29/2016 8:52:20 PM)

The data is a little odd. The normalized data (red line) of all other data for the 75mm APC doesn't carry as well the O.B. data for the same round (green line.)


[image]local://upfiles/21308/B9BADFFAA5AA448EB38AAACF71B343A6.jpg[/image]



Elron Hubbub -> RE: German 75mmL43, L48 and L46 velocities (8/29/2016 9:10:20 PM)

British Armor? British penetration definitions?

Does the other OB values seem inline?



Mobius -> RE: German 75mmL43, L48 and L46 velocities (8/29/2016 11:38:15 PM)

quote:

ORIGINAL: Elron Hubbub

British Armor? British penetration definitions?

Does the other OB values seem inline?

The L48 does seem to follow the Aberdeen path.

The 2400f/s data is in blue all other 75mm/L48 are red data. Two red sets are almost the same and they are from Aberdeen and what may be British data.

(It gave me an opportunity to improve my data averaging and normalizing program.)


[image]local://upfiles/21308/FE0C022A12E34B0D8E0B08A5BD8D51F0.jpg[/image]



Elron Hubbub -> RE: German 75mmL43, L48 and L46 velocities (8/30/2016 3:07:32 AM)

Pak 40 MV 2600 f/s (792.48 m/s)? I assume you meant Pak 40?



Mobius -> RE: German 75mmL43, L48 and L46 velocities (8/30/2016 3:27:27 AM)

Oops sorry, I corrected it. It is the first one on the list, 2400 f/s. KwK 40



Mobius -> RE: German 75mmL43, L48 and L46 velocities (8/30/2016 2:58:43 PM)

Here's another graph of different data collections and subsets.
The red line is the average of all the 75mmL48 data points. About half are German and half are British. They are from different sources though there probably are duplicates as who can tell what an author uses?

The blue line is raw Aberdeen data. But I don't know if Aberdeen did their own testing or worked with the British. The pink line is the same data but normalized.

The green line is the 2400 f/s O.B. data. It seems to be similar to normalized Aberdeen data. It also doesn't track with other British data of the red collection.

[image]local://upfiles/21308/A69435E898E34568AECE11ED0A819030.jpg[/image]



Elron Hubbub -> RE: German 75mmL43, L48 and L46 velocities (8/30/2016 3:12:28 PM)

O.B./43/CV.12 May 25,1943
shows for 2400 f/s muzzle velocity (731.52 m/s) of 14.81 lb. APCBC shell ("MV as tested by trial in KwK 40") at 0 and 30 degrees deflection:
2400 f/s penetration 121/102 mm,
2000 f/s (609.6 m/s) 98/83 mm,
1600 f/s (487.68 m/s) 75/63 mm.

Given the date, I would almost have to think this is a L43 gun. If it was a StuG, it might be a L48, but the KWK 40 (Panzer IV) held onto the L43 longer.



Mobius -> RE: German 75mmL43, L48 and L46 velocities (8/30/2016 3:47:37 PM)

quote:

ORIGINAL: Elron Hubbub
Given the date, I would almost have to think this is a L43 gun. If it was a StuG, it might be a L48, but the KWK 40 (Panzer IV) held onto the L43 longer.

2400 f/s is only MV of 732m/s so it's probable. I'll have to see how it compares with other L43 data.

It does show that the Pzgr. 39 was out before Kursk. What the Russians were testing after Kursk to get low penetration numbers is confounding.



Mobius -> RE: German 75mmL43, L48 and L46 velocities (8/31/2016 2:58:01 AM)

Here is how the 2400 f/s O.B. values compare to other 75mm/L43 data.
Seems a little high.

[image]local://upfiles/21308/52C055C800DA436886B1AD7C8A4E719A.jpg[/image]
And then I found this War Office memo.

WO 185/178, Tank armament versus armour 1943
"Thickness of armour penetrated by 80% of projectiles striking the plate at an angle of 30º to the
normal":
----------------------------MV armor 500 yds 1000 yds 1500 yds
7.5 cm KWK 40 APCBC 2400 MQ 89 79 62

The 80% number seems like something the Russians were doing with their certified penetration criteria.

A memo from the Ministry of Supply dated 1st April 1943 gives the following figures for "Single homo
plate penetration at 30º in mm."
------------------500--1000--1500--2000
7.5cm KwK40 APCBC 89 79 70 62





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