Short barreled Pak 40
Re: Short barreled Pak 40
Hi Alain
I have also read in many books your version , but I never found or see any original information to prove this .
Waffen Revue are all based on first hand German information and all facts given by Peeved makes me to
change my opinion on this subject .
Regards Jos
I have also read in many books your version , but I never found or see any original information to prove this .
Waffen Revue are all based on first hand German information and all facts given by Peeved makes me to
change my opinion on this subject .
Regards Jos
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Re: Short barreled Pak 40
Well, regardless of what it may say just look at the gun, all the parts are clearly Pak 40, breech, barrel and recoil slide beneath the barrel. The evry idea that a Pak 38 barrel had enough thickness in its walls to allow it to be rebored from 50mm to 75mm is actually a bit beyond belief.
Alan
Re: Short barreled Pak 40
The Pak 50 breech is quite obviously from a Pak 38 which can be seen comparing pictures 1.jpg and Pak38.jpg on page 1; Pak 40 e.g. had a much longer breech ring as shown at http://en.wikipedia.org/wiki/File:Pak40 ... i_rear.jpg , totally different operating lever etc.
Comparing the pic below showing both the Pak 38, 50 and 40 barrels in approximately same scale it can be seen that both the Pak 50 barrel and modified cradle have been moved forward, quite natural when trying to maintain trunnion balance with a shortened and bored out barrel. Comparing the Pak 38 and 50 barrel diameters in the pic also shows that reboring the 5 cm Pak to 7,5 cm appears not to have been beyond WW II German belief. After all the reboring affected the thicker breech end of the barrel which was rechambered to take a relatively low velocity (compared with the Pak 38) 7,5 cm cartridge.
Comparing the Pak 50 with Pak 40 IMO shows little support to your claim:
Markus
Edit: Just noticed that two pics last page; Pak50-1.jpg used in the composite below and the photo it's apparently drawn from, Pak50-5.jpg from the US intelligence report, are based on a reversed negative. That doesn't change the dimensions I used in the comparison above but downloaders might want to use the mirrored pics below.
Comparing the pic below showing both the Pak 38, 50 and 40 barrels in approximately same scale it can be seen that both the Pak 50 barrel and modified cradle have been moved forward, quite natural when trying to maintain trunnion balance with a shortened and bored out barrel. Comparing the Pak 38 and 50 barrel diameters in the pic also shows that reboring the 5 cm Pak to 7,5 cm appears not to have been beyond WW II German belief. After all the reboring affected the thicker breech end of the barrel which was rechambered to take a relatively low velocity (compared with the Pak 38) 7,5 cm cartridge.
Comparing the Pak 50 with Pak 40 IMO shows little support to your claim:
In addition to the Pak 40 breech being quite different, its barrel is of larger diameter and its barrel contours are a poor match.just look at the gun, all the parts are clearly Pak 40, breech, barrel and recoil slide beneath the barrel
Markus
Edit: Just noticed that two pics last page; Pak50-1.jpg used in the composite below and the photo it's apparently drawn from, Pak50-5.jpg from the US intelligence report, are based on a reversed negative. That doesn't change the dimensions I used in the comparison above but downloaders might want to use the mirrored pics below.
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Re: Short barreled Pak 40
So you really think that the barrel of a 50mm gun was thick enough to allow it to be rebored by 50% ?
Alan
Re: Short barreled Pak 40
I'm quite convinced that it was feasible considering the fact that the guns AFAIK were rebored for the same relatively low-velocity and pressure ammo as the 7,5-cm-KwK 37 L/24 "Stummel". The captured Pak 50s don't seem to have suffered ill effects from test firing if any.
IMO a more adventurous German reboring effort was turning captured Soviet 7,62 cm AA guns into lightweight 8,8 cm Flaks.
Markus
IMO a more adventurous German reboring effort was turning captured Soviet 7,62 cm AA guns into lightweight 8,8 cm Flaks.
Markus
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Re: Short barreled Pak 40
Markus, The reboring on the Soviet Flak guns was only 10%. Where did you read that the ammo was from the L/24 ?
Alan
Re: Short barreled Pak 40
The 15% calibre increase in the 7,62/8,8 cm Flak conversion was relatively speaking small but the Soviet guns were rather lightly built in the first place and this was a HV to HV ammo conversion whereas the Pak 50 was a HV to LV one.The reboring on the Soviet Flak guns was only 10%.
E.g. the "Organisations-Abteilung III des OKW" war-diary entry from WR 102 mentioned earlier:Where did you read that the ammo was from the L/24 ?
continuedOn 1. 10. 1943 the Führer was introduced the 5-cm-KwK and Pak 38 rebored to 7,5 cm.
The L/24 calibre is also mentioned in Speer protocols etc.Therefore the OKW orders that of the 5-cm-barrels in the area of Ob.West 1000 are to be rebored to use the 7,5-cm-LwK-L/24 ammunition.
Also the Intelligence Report from 17th July 1945 quoted in WR 102 notes that the Pak 50 with barrel number R 272 had a range drum calibrated for 7,5-cm-Gr.Patr.38 and 7,5-cm-Gr.Patr.KwK (ammo types of the 7,5-cm-KwK L/24). Additionally the chamber length of 256 mm stemming from the report corresponds nicely to the 7,5-cm-KwK L/24 case length of 243 mm.
Markus
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Re: Short barreled Pak 40
Does this WR 102 happen to say how many rounds the gun could fiore before the barrel melted ? The walls of the barrel can't have been more than a couple of mm thick, hoo hum !
Alan
Re: Short barreled Pak 40
Measuring from the retouched photo against known ordnance length of 2240 mm with muzzle brake I'd say the visible front end of the Pak 50 barrel is about 107 mm in diameter. That would still have left ca. 16 mm wall thickness around the thinnest point; more than e.g the 12,5 mm in the muzzle of 5-cm-KwK L/42. The Pak 50 muzzle also appears heavily hooped behind the muzzle brake. Sometimes a couple of mm appear adequate.
Markus
Markus
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Re: Short barreled Pak 40
I do have to ask as well, just what the point of doing all that work to a Pak 38 to give it an inferior anti-tank capability ? The small increase in HE performance doesn't seem to be worth the effort. The idea of the Pak 50 was supposedly to provide a lighter gun with a similar a/t performance tro the Pak 40, the Pak 38 was already better than the KWK 37 so why do all that work reboring (which you will never convince they did) and rechambering ? All they needed to do was adjust the fittings to get a shortened Pak 40 barrel into the Pak 38 carriage. The Pak 50 as described by this WR 102 is a compleytely illogical waste of effort while the Pak 50 as described in Hogg's Artillery book and Lexikon der Wehrmacht is at least based on a bit of sense.
Alan
Re: Short barreled Pak 40
Hello
First I repected every one's opinion , but can you tell me the reason why a barrel of a shorted PaK 40 was placed on a
carriage of a PaK 38 and not just only to shorted the barrel of the PaK 40 and leave it on the carriage of the PaK 40 ,
this would save's a lot of manhours and workplaces in the last years of the war ?
Regards Jos
edit
Please see also this the PaK 37 later I.G. 37 fired as PaK Hohlladungen , so this could also be the case for the PaK 50
Von der Firma Krupp stammte die 510 kg schwere 7,5-cm-Pak 37. Das Provisorium stellte eine Kombination zwischen einem Infanteriegeschütz und einer Pak dar. In die Lafette der 3,7-cm-Pak wurden 1.800 mm lange Rohre vom Kaliber 7,5cm mit einer Länge von 1.800 mm eingebettet. Später wurden auch russische Beutelafetten benutzt. Bei einer v0 von 280 m/Sek. wurden Schußweiten bis 5.150 m erreicht. Die zur Panzerabwehr verwendete Hohlladungsgranate durchschlug mit ihren 0,5 kg Sprengstoff Panzerungen bis zu 85 mm bei einer v0 von 395 m/Sek. Im Mai 1944 stufte das Waffenamt die Geschütze als Infanterie-Geschütz 37 neu ein. Im Juni 1944 wurden die ersten 84 Waffen an die Truppe ausgegeben, bei Kriegsende waren noch 1.304 Waffen bei der Truppe. Die Waffen hatten einen Schwenkbereich von 60° und eine Rohrerhöhung von -5° bis +24°.
Info = Lexikon der Wehrmacht
First I repected every one's opinion , but can you tell me the reason why a barrel of a shorted PaK 40 was placed on a
carriage of a PaK 38 and not just only to shorted the barrel of the PaK 40 and leave it on the carriage of the PaK 40 ,
this would save's a lot of manhours and workplaces in the last years of the war ?
Regards Jos
edit
Please see also this the PaK 37 later I.G. 37 fired as PaK Hohlladungen , so this could also be the case for the PaK 50
Von der Firma Krupp stammte die 510 kg schwere 7,5-cm-Pak 37. Das Provisorium stellte eine Kombination zwischen einem Infanteriegeschütz und einer Pak dar. In die Lafette der 3,7-cm-Pak wurden 1.800 mm lange Rohre vom Kaliber 7,5cm mit einer Länge von 1.800 mm eingebettet. Später wurden auch russische Beutelafetten benutzt. Bei einer v0 von 280 m/Sek. wurden Schußweiten bis 5.150 m erreicht. Die zur Panzerabwehr verwendete Hohlladungsgranate durchschlug mit ihren 0,5 kg Sprengstoff Panzerungen bis zu 85 mm bei einer v0 von 395 m/Sek. Im Mai 1944 stufte das Waffenamt die Geschütze als Infanterie-Geschütz 37 neu ein. Im Juni 1944 wurden die ersten 84 Waffen an die Truppe ausgegeben, bei Kriegsende waren noch 1.304 Waffen bei der Truppe. Die Waffen hatten einen Schwenkbereich von 60° und eine Rohrerhöhung von -5° bis +24°.
Info = Lexikon der Wehrmacht
Re: Short barreled Pak 40
Only provided the Pak 38 was using PzGr 40 which became a no-no due to the tungsten shortage, 1943 being the last 5-cm-PzGr 40 production year. Hohlladungsgranate 38 C of the 7,5-cm-KwK 37/L/24 pierced 75 mm of armour at all distances which the 5-cm-PzGr 39 from a Pak 38 only matched at point blank ranges (as usual German penetration figures being given at an 60 deg. angle of impact). I guess the Germans were wrong in e.g. arming late production Pz IIIs with the 7,5-cm KwK 37 instead of the 5-cm KwK then and positive reports from the front regarding the change were erraneous also?Alanmccoubrey wrote:I do have to ask as well, just what the point of doing all that work to a Pak 38 to give it an inferior anti-tank capability ?
By Jingo, let's ditch the 155 mm guns (not worth the effort) and go back to 105 mm if only a small increase in HE performance results from an almost 200% weight increase; from the 1,96 kg 5-cm-SprGr to the 5,75 kg 7,5-cm-SprGr 34?The small increase in HE performance doesn't seem to be worth the effort.
According to which primary source? The German contemporary view appears to have been the need to make use of old 5-cm barrels that were no more effective against enemy armour.The idea of the Pak 50 was supposedly to provide a lighter gun with a similar a/t performance tro the Pak 40,
Penetration-wise compared to the Hohlladungsgranate 38 C only with PzGr 40 as noted before.the Pak 38 was already better than the KWK 37
Some people will tend to believe the monkey... In this case I'd listen to the organ grinder.so why do all that work reboring (which you will never convince they did)
And get that Pak 38 breech block blown straight out. Or do you still believe that the Pak 50 had a Pak 40 breech despite photographical and numerical evidence to the contrary?and rechambering ? All they needed to do was adjust the fittings to get a shortened Pak 40 barrel into the Pak 38 carriage.
If anything it was too little gun for the carriage which may have been the reason why it appears not to have been produced in quantity whereas the significantly lighter I.G. 37 conversion and its I.G. 42 derivative were well thought of and mass-produced although production never caught up with the demand. After all the somewhat instable 7,5-cm-Pak 97/38 conversion would've had a better ballistic performance on the Pak 38 carriage. E.g. would have made more sense to continue the Pak 97/38 conversions and ditch the Pak 38 uppers to coastal and land fortifications than produce the Pak 50.The Pak 50 as described by this WR 102 is a compleytely illogical waste of effort
The Pak 40 chop shop theory is based on little sense although it would have been a blast... Muzzle blast; merely wasting ballistical potential in a barrel about half the length of the one intended by the Pak 40 designers.while the Pak 50 as described in Hogg's Artillery book and Lexikon der Wehrmacht is at least based on a bit of sense.
In fact Waffen Revue 102 asked several questions pertinent to the Pak 40 shortling theory:
Since the 7,5-cm-Pak 40 was manufactured until the end of the war (Hitler himself demanding increased production) and was urgently needed for installation in fortifications, SPGs etc.
1) Why would Pak 40 barrels be manufactured to be shortened?
2) Even if such barrels had been used is there any reason why the breech mechanism was altered. The Pak 40 breech was excellent and would have worked just as well with a shortened barrel.
3) Like Jos, WR also asked why a shortened Pak 40 would be put on a Pak 38 carriage which would have to be altered for that purpose.
Additionally why do you AOT ignore the Intelligence Report from 17th July 1945 quoted in WR 102 which makes it obvious that the Pak 50 didn't use Pak 40 ammunition?
Markus
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Re: Short barreled Pak 40
I'm not ignoring the WR 102, I'm asking you why you think that the Germans went to all that trouble for something that was no better than the gun they wasted all the effort changing. I don't really think that any US int report can be called the organ grinder either ! Nor for that matter should you be calling Ian V Hogg a monkey !
Alan
Re: Short barreled Pak 40
As shown previously the 7,5-cm L/24 had a better AP and HE performance than Pak 38 (without PzGr 40) and the Germans obviously knew that. To repeat the quote from the Organisations-Abteilung III des OKW war diary from 3.10.1943:Alanmccoubrey wrote:I'm not ignoring the WR 102, I'm asking you why you think that the Germans went to all that trouble for something that was no better than the gun they wasted all the effort changing.
Anyhoo based on available information the Pak 50 remained experimental at a small scale so any effort expended was relatively minor. As noted before the gun was ballistically bantam weight for the carriage which may have been a contributing factor to the Pak 50 remaining experimental.2) 7,5-cm-Pak 50 (Pak 38 rebored)
a) Performance increase of the former 5-cm-Pak.
OTOH in 1942 the Germans were seriously contemplating wedding the 5-cm-KwK L/42 to ex-Soviet 45 mm AT gun carriages considerably lighter than the Pak 38 one. Since the L/42 was one of the guns considered for the 7,5-cm conversion it appears that a lighter 5-cm to 7,5-cm conversion than the Pak 50 would have been feasible.
The US intel report being a primary document which doesn't conflict with original German ones, carries more weight than the efforts of later writers who, based on info in WR 102 may have been mimicking (monkey see, monkey do) a mistranslation from the US report in Die deutschen Geschütze 1939-1945 by F.M. von Senger und Etterlin, first published in 1960. The mere fact that it is obvious to the naked eye that the Pak 50 barrel diameter and contours in addition to the breech are totally different from Pak 40 but similar to the Pak 38 should have convinced even laymen that the amputated Pak 40 theory was bogus even before the Waffen Revue revealed factual documents behind the gun development and tech data of captured examples.I don't really think that any US int report can be called the organ grinder either ! Nor for that matter should you be calling Ian V Hogg a monkey !
Markus
Last edited by peeved on 03 Jun 2009, 13:32, edited 1 time in total.
Re: Short barreled Pak 40
I'm sure the reboring of 50mm A/T guns consisted not so much of boring them out, but of re-linering the outer casing of the barrel. This is what was done to the British 6 pdr. to 75mm conversion.
As far as Ian V. Hogg and monkeys are concerned, I have highlighted pages of gross errors in his books in my collections!
As far as Ian V. Hogg and monkeys are concerned, I have highlighted pages of gross errors in his books in my collections!