rexford

I scanned the German pages on Russian SchrPatr ammo and will e-mail them to whoever wants copies. There are five scanned pages which cover ten pages from the manual. E-mail me at rexford179@cs.com One of the drawings shows the SchrPatr being fired against troops on a hillside, where the round follows a smooth trajectory to just before the target, where the SchrPatr ammo explodes ("sprengpunkt" or bursting point). If the round must be set for a given fuze detonation range, this would introduce range estimation error into the casualty equation. [ May 31, 2003, 04:05 AM: Message edited by: rexford ]

The John Salt site has some studies on suppressive effect where projectiles above a certain velocity, which are within a certain distance from a man, have a good chance of suppressing the fellow. Plenty of assumptions would go into who gets suppressed. Even John Wayne was occasionally pinned down by inaccurate, but close miss, fire. And if the Duke kept his head down, lesser mortals would. [ May 31, 2003, 03:48 AM: Message edited by: rexford ]

The following translation by Tar seems to suggest that Russian Schr. Patr. ammo was schrapnel, since the translation refers to a fuze. The drawings of Russian 7.62cm Schr. Patr. show a projectile with a nose piece (Dopp Z 436® russ T-6), a compartment filled with balls, and then an area under the middle compartment that appears to contain a powder substance. I can scan the drawings and explanation of effective area and share with whoever would like to see it. The one point that sticks out in my mind is that cannister is normally fired from guns without muzzle brakes, such as U.S. 37mm and 75mm guns and the German 75mm L24, while the 76.2mm field gun vet on the Russian Battlefield talks about case shot but his gun would seem to have had a muzzle brake. If the 76.2mm field gun fired schrapnel, it would seem more likely to be a fuzed round than a cannister that started to spread as soon as it left the barrel (but before it left the muzzle brake). Based on Tar's improved interpretation, which is appreciated very much, Russian schr. patr. appears to be schrapnel that explodes at a distance from the gun and then spreads out. The Russian 45mm and 57mm anti-tank guns did not have a muzzle brake. Instructions for shooting with Russian shrapnels. The cone of dispersion has an average angle of 15°, which means that the balls hitting at a distance of 80m cover an area 20m wide. The length varies depending on the angle of impact. The fuse setting given in the firing table sets the mean bursting point 80m horizontally along the line of fire before the target. It will appear to the observer of the gun to be slightly above the target (2 to 5)[m?] Because of the dispersion, a small number of the balls will inevitablely strike the ground. (Therefore also AZ [huh?]). These balls are ineffective, but have to be tolerated, since, on the other hand, a detonation that is too high above the ground will not have any effect. </font>

I have a German report on 7.62cm ammo, and there is a big section entitled "Anleitung zum Schiessen mit russischen Schrapnells". Guidance for shooting with Russian shrapnels Shows a gun firing and the little balls are spreading out and forming a roundish shape on the ground. Cross sectional drawings of the various projectiles show lots of tiny balls in each 7.62cm Schr. Patr. projectile. "Der Streukegel hat einen Winkel von durchschnittlich 15°, das heisst, die Kugeln treffen in 80 m Enterfernung eine Flache von 20 m breite: die Lange ist je nach dem Einfallwinkel verschieden" Translated as: "The strewing cone has an angle of on the average 15 degrees, i.e., the balls meet a flat from 20 m broad in 80 m Enterfernung: the long one is different depending upon the angle of incidence" The drawing that goes with the above statement shows a 20m wide oblong shape on the ground at 80m range from the gun, with balls landing all over the shape. "Die Zunderstellung in der Schusstafel ist so angegeben, dass der mittlere Sprengpunkt fur Ziele in der mundungswaagerechten 80 m vor dem ziel liegt. Er wind dem beobachter vom Geschutz knapp uber dem ziel (2 bis 5) erscheinen. Jnfolge der streuung wird eine kleine anzahl von geschossen unvermeidlich am boden aufschlagen. (Deshalb auch AZ). Diese sind nahezu wirkungslos, mussen aber in kauf genommen werden, da andererseits auch zu hohe sprengpunkte keine Wirkung haben". The scale position in the firing table is in such a way indicated that the middle bursting point lies fur goals in the mouth-horizontal 80 m before the goal. It wind the observer of the Geschutz the goal (2 to 5) appear scarcely more uber. Jnfolge of the dispersion a small number of shot inevitable at the soil to impact. (therefore also AZ). These are almost ineffective, mussen however in purchase to be taken, since on the other hand also to high bursting points do not have effect Balls that hit the soil are ineffective? There is a firing table for 7.62cm Schr Patr fired at several muzzle velocities. At 626 m/s, the 50% scatter pattern has a height of 1.1m at 1000m and a length of 55m. "Ein Teilstrich der Zunderstellung verlegt d. Sprengpunkt nach der Hohe Lange" What does this all mean?

If infantry are in the woods, the cannister effect will be reduced due to: 1. lying down instead of standing up decreases target area, and cannister will spread out vertically so some of the balls will fly over a standing man and many may miss a lying one 2. infantry will be spread out laterally, which means one has to compare spread of cannister to spread of infantry on the ground 3. trees will take hits and absorb cannister energy, and occasionally bounce balls here and there

Really good post that summarizes the best info around, which hopefully will get things changed. Looking at CMBB just now, IS-2 Model 1944 has 120mm on the 60 degree glacis and the 30 degree nose. [ May 29, 2003, 05:25 AM: Message edited by: rexford ]

Good eyes, sir! Also note that Figure 6 shows 100mm for IS-2 nose armor in all cases.

Vasiliy Fofanov posted some data from the book on the Tankers site some time ago, 100mm nose armor at 30 degrees from vertical on all IS-1 and IS-2 tanks except that 90mm rolled substituted for 100mm cast on IS-2 Model 1944. Alfred noted on the Russian Battlefield site that the Svirin book has 75mm for IS-2 mantlet. Drawings show a tapered mantlet thickness, with 75mm at bottom and top thickening towards the middle where it is either 100mm or 110mm. Tiger mantlet thickness for a long time was based on the thinner tapered top and bottom areas, even though the central mantlet exceeded 130mm in most locations. Panther mantlet armor is also tapered with thinnest sections at top and bottom and maximum at apex.

Did you read my recent post where I explained all of the guns and ammo that was fired during the British tests in Cairo during 1942. In the British tests against PzKpfw IIIH front hull, which we have in a U.S. report: 2 pdr AP broke up and failed at 200 yards 6 pdr AP clean penetration of driver plate at 600 yards clean penetration of nose armor at 500 yards 37mm APCBC 3 partial penetrations at 200 yards vs driver plate 1 complete penetration at 300 yards vs driver plate 75mm Grant AP 1 complete penetration at 500 yards vs driver plate partial penetration at 600 yards with damage to main armor 75mm Grant APCBC Clean penetration at 1000 yards, little remaining energy after penetration Firing Test against PzKpfw IIIH side hull 2 pdr AP clean penetration at 1500 yards

What does the book have for front hull armor on IS-1 and Model 1943 IS-2, and are thickness figures given for the mantlet and turret front on all versions?

Jason C has posted: "The 69mm figure, on the other hand, implies that 25 pdr AP should start failing at 500m, against typical tactical angles (30 degree combined angle). This is not what DAK reported about the effective range of 25 pdrs against Pz III Hs. They report those killed at 1000m, even with the SOP of rotated hulls. Pz IIIs preferred to engage from as far as 1500m, to stay well outside the lethal envelope of 25 pdrs." Please reference the above statement and give us the exact words if possible, because the above post could be very important and help resolve the issue. According to our calculations, the North African 25 pdr AP could penetrate 60mm face-hardened at 1000m, which would fit 57mm resistance from the 32mm/30mm face-hardened in-contact combo. Advanced Squad Leader indicated that about 325 PzKpfw IIIH were produced, and other PzKpfw IIIG were uparmored by adding extra plates. It would seem that more than a handful could have been in Africa at one time. The wargame TOBRUK (May 1942 battle) had all PzKpfw III as Ausf H if I remember correctly, which I always thought was a slightly optimistic view. So if Jason C would be so kind as to reference his statement on 25 pdrs vs PzKpfw IIIH we might have resolution this week.

Jason C posted the following: "It seems to me questionable to base estimates of the effectiveness of a given plate against 76mm and 88mm caliber shells on reports of the effectiveness of 40mm caliber shells. The diameter to thickness ratios are so far apart that expected shatter behavior is quite different." The British tests against the front of a PzKpfw IIIH were previously described in detail on this site, maybe even on this thread, and included the following guns and ammo: U.S. 37mm APCBC British 2 pdr AP British 6 pdr AP U.S. Grant 75mm AP U.S. Grant 75mm APCBC German PzKpfw IV 75mm APCBC So Jason C's conclusion that all of the 69mm stuff against 76.2mm and 88mm ammo is based on a few tests with 2 pdr AP ammo is not the case.

Does the penetration data for German 37mm AP in British Report WO 190/706 give the armor tensile strength for the plate penetrated by that round? The excerpt from the report on your site states that the tankbusche was tested against 170 kg/mm squared plate, which is about 450 Brinell Hardness. If a figure is given for the 37mm plate strength it would be of great significance in the interpretation and prediction of 37mm Pak performance against French and Russian tanks.

The John Salt site presents excerpts from a 1938 German report where 37mm ATG penetration is given as (angles revised from German to American WW II systems, where Germans treat vertical as 90 degrees and Americans as 0 degrees): 650 yards 33mm against vertical plate 26mm against 30 degrees from vertical 765 yards 14mm against 45 degrees from vertical 1090 yards 22mm against 30 degrees from vertical If the 37mm Pak penetrated 33mm vertical plate at 650 yards, the 100m penetration would be around 40mm. The above data is consistent with some reports that 37mm Pak AP had troubles against French tanks during 1940 combat and against Russian T34. If the 33mm plate were high hardness plate at about 450 Brinell Hardness, the British National Physical Laboratory equation predicts that a lower thickness of 300 Brinell plate would be penetrated. However, there is a chance that the 37mm AP penetration data is against 450 Brinell Hardness plate since the tankbusche performance is given against 170 kg/mm squared tensile strength plate and the plate thickness is 35mm in one case. Unless the 33mm plate were face-hardened or high hardness, the 1938 data suggests that early war 37mm AP ammo may have been inferior to the projectiles used for much of the published penetration data for German 37mm AP. The above data for 1938 performance of 37mm AP was taken from report WO 190/706 presented on site at http://salts.britwar.co.uk/ Browse documents WW II Weapon Penetration Tables WO 190/706 [ May 25, 2003, 10:42 PM: Message edited by: rexford ]

Still "normal" hits are at 0 deg obliquity, this is how the British tested versus German tanks in Africa 1941. Unless the pattern changed completely in 1942 I think that this still holds true, this practice (O deg as "normal hits") continued in Normandy. The 30 deg standard on the other hand is always suffixed as such, which is the complete opposite of German practice. (30 deg hits are "normal" and 0 deg ones are suffixed). [/QB]</font>

Lt. Col. H.D. Drew who undertook the tests, carried them out at "broadside/normal impacts" or 0 deg angles unless other wise stated. The first Int Summery dated May 1941 for instance stated in yards the distance for normal impacts (0 deg) vunrability on German Mks I, II, III and IVs and then noted 30 deg engagement ranges for 30mm, 40mm and 45mm armour. </font>

Alfred on the Russian Battlefield forum posted the following on IS-2 armor: "I bought Mikhail Svirins book on the IS-2 tank. Svirin includes a diagram of the IS-2(1944) armor values. The sloped variant IS2(1944) has 100mm cast armor both on the nose and glacis front hull. There was also the parallel production run with 90mm Rolled armor on both glacis and lower front nose . Looking at your site I see: <http://www.battlefield.ru/tanks/is2/is2_16_1.gif> Where is this 120mm figure coming from? Mikhail Svirins book has design blueprints as refrences to his figures. Who is right?, I am confused and need to know which are the correct armor values for a modell I am building." Alfred seems to make a good point.

Using enemy weapons is a real risk. 1. American infantry picked up German machine pistols and used them against some Wehrmacht in a town, nearby Americans called down artillery on their own troops after hearing the distinctive machine pistol sound which they associated with the Germans. 2. A Russian metal winner in a Matilda was killed by anti-tank fire from Russian ground troops that saw a tank they didn't immmediately recognize as Russian (strange looking tank in their eyes).

Given the verbiage in his posts, I would say probably still typing his response. </font>

There are two schools on the effectiveness of the PzKpfw IIIH 32/30 layered combo, where the plates were in contact. British firing tests in Africa showed that the 32mm/30mm face-hardened layered armor was equivalent to a single 69mm face-hardened plate. The only question is whether the tests were conducted with the gun aiming directly at the hull front, or if there was a 30 degree angle from gun to hull facing. Nothing in the report on firing angle (so much for Allied thoroughness). With a 30 degree side angle, 32/30 resists like one 57mm thick face-hardened plate according to my calculations. 32mm/30mm layered armor on PzKpfw IIIH, and the layered armor on PzKpfw IVG, was a hasty attempt to uparmor tanks. The bolts on the PzKpfw IIIH tended to shear on angled hits, and it became a maintenance headache. To weld two face-hardened plates together requires that the areas around the edges be free of face-hardening. Anyway, making two face-hardened plates is a major headache compared to making one face-hardened plate, since that type of armor takes a long time to produce and requires alot of skill. A single 50mm face-hardened plate may resist with a little less effective thickness than 32/30, but it allows more tanks to be built. And a 76.2mm APBC round will destroy 32/30 and 50 face-hardened at long ranges if those British tests were at 30 degrees side angle.

One of the interesting things about the T34 penetration resistance is that most people disagree. The Mr. Potapov who runs the Russian Battlefield site saw a Russian firing trial where 75L43 APCBC blew through the T34 front hull at 1000m with a 30 degree angle from gun to hull facing. One of the 1942 reports in Jentz' Panzertruppen Volume I has 75L43 penetrating T34 at 1200m at any angle, and 1600m max. And then there are the reports from German generals where 75mm L46 Pak hits bounce beyond 1000m, and combats where 75L43 won't penetrate beyond 1000m. All of this kinda makes one wonder one was happning. Was it crummy ammo? Krypnotite in the armor? A bad hair day? Very wide side angles on the shots? Some of the T34 had extra plates welded on the front hull which were not noticed by the panzertruppen? Past arguments speculated that the Americans not only built Russian armor factories before WW II started under the guise of installing tractor plants, but sold the Russians several shiploads of armor steel which found its way into some of the T34. Typical high hardness plates for 45mm front hull on T34 would be an easy target at 1000m and could be blown through at 1600m max. Medium hardness armor of so-so quality, like American plates, might stop 75mm APCBC beyond 1000m. Miles Krogfus found that German projectile nose hardness varied from 57 to 69 Rockwell C Hardness, where the middle would be 63 Rockwell C. 75mm APCBC at the lower end of the hardness range could penetrate quite a bit less than the average round. So, in summary, from what I've read it would be realistic if T34's were not the same all the time.

The John Salt site has some interesting stats on German APCR vs the type of high hardness armor that one might find on a T34 (400 Brinell Hardness and higher). Go to: http://salts.britwar.co.uk/mod.php?mod=fileman&menu=8&PHPSESSID=dfd706a9d7dd1e23402bb67dfd962871 then Browse Documents then WW II Weapon Penetration Tables then Braun 1977 3cm APCR penetration is given against armor with tensile strength of 100 and 150 kg/mm squared, which corresponds to 284 and 421 Brinell Hardness. 100m penetration of 3cm APCR 284 Brinell Hardness, 100mm vertical and 58mm at 30 degrees from vertical 421 Brinell Hardness, 078mm vertical and 47mm at 30 degrees from vertical Penetration of 3cm APCR is strongly influenced by plate hardness. Slope effect at 30 degrees from vertical for 3cm is rather high compared to 76mm HVAP, being about 1.7. Penetration data for 37mm Flak 18 APCR is given against 150 kg/mm squared plate (421 Brinell Hardness) as 140mm vertical at 100m, with 68mm at 30 degrees from vertical. Slope effect at 30 degrees from vertical is 1.47, much higher than 76mm HVAP. A graph for 3cm APCR penetration which extends from vertical plate penetration to 45 degrees from vertical indicates that the difference in penetration between 284 and 421 Brinell Hardness plate decreases as the angle from vertical increases, so results should be similar at 60 degrees from vertical. Net Surfer Bird

Miles Krogfus has recently noted that Russian manuals for T34 indicate 655 m/s for 76.2mm APBC. Based on 655 m/s muzzle velocity and analysis of U.S. firing trials with 100mm and 122mm APBC, an ARTKOM equation estimate for T34 76.2mm APBC against medium hardness rolled homogeneous armor is 81mm vertical at 0m. This is for BR-350B with typical heat treatment. The 500m penetration would be 70mm of vertical homogeneous armor (medium hardness), for typical APBC, which is inadequate against Tiger side 82mm plate unless plate is "bad". With special heat treatment BR-350B, the 400m and 600m penetration would be 79mm and 74mm homogeneous, which would square with some reports of T34 penetrations at 400m and bouncers at 600m. ========================================================== U.S. firing trials with 122mm APBC resulted in 127.5mm vertical penetration at 655 m/s, against medium hardness rolled homogeneous armor. Applying the ARTKOM equation to the 122mm APBC penetration at 655 m/s, the C constant for 122mm APBC is 2380. If the same constant is applied to 76.2mm APBC (BR-350B) at 655 m/s, the 0m vertical penetration for the T34 tank gun is 81mm. 81mm penetration at 0m and vertical would make penetration of the Tiger 82mm side armor difficult at any range and angle. ========================================================== The U.S. firing trials with 100mm APBC can also be used to estimate 0m penetration for 76.2mm BR-350B, and the result is 82mm vertical. Because the U.S. tests with 100mm APBC were against cast armor, they were converted to homogeneous plate using the equation we developed for good quality cast and rolled armor. Examining the results, it appears that the U.S. cast armor contained additional deficiencies, based on comparison with British tests of a captured SU 100 and ammunition (John Salt site, report DEFE 15/1107): 0m Penetration Comparison ==================== 30 degrees, 164mm rolled (British), 165mm rolled cast equivalent (U.S.) 45 degrees, 133mm rolled (British), 151mm rolled cast equivalent (U.S.) 60 degrees, 96mm rolled (British), 104mm rolled cast equivalent (U.S.) 70 degrees, 59mm rolled (British), 62mm rolled cast equivalent (U.S.) Rolled cast equivalent is after the cast thickness has been converted to rolled thickness, and the above figures suggest that the cast armor was not highest quality. 915m Penetration Comparison ====================== 30 degrees, 140mm rolled (British), 150mm rolled cast equivalent (U.S.) 45 degrees, 115mm rolled (British), 135mm rolled cast equivalent (U.S.) 60 degrees, 84mm rolled (British), 88mm rolled cast equivalent (U.S.) 70 degrees, 51mm rolled (British), 52mm rolled cast equivalent (U.S.) U.S. cast armor in the 100mm to 127mm thickness is 5% to 17% less resistant then it should be, which suggests flaws or other problems with penetration resistance. At 655 m/s, the 100mm APBC penetrates 5.08" of U.S. cast plate, which is equivalent to 4.95" using a cast-to-rolled armor deficiency equation. This thickness would be reduced by 10% to model additional penetration resistance problems with the castings. 100mm APBC at 655 m/s would have an ARTKOM constant of 2356 against medium hardness rolled armor, which is similar to 122mm APBC. Applying the 2356 C constant to the ARTKOM equation for 76.2mm BR-350B at 655 m/s results in 82mm of vertical RHA at 0m. ======================================================== It should be noted that the ARTKOM equation C constant for APBC against rolled homogeneous armor plate varies with velocity and is not a true constant. While the ARTKOM equation assumes that penetration varies as velocity raised to 1.43 power, the U.S. tests with 122mm APBC showed the penetration to vary as the velocity raised to the 2.5 power down to 671 m/s, and to the 1.8 power below that.

Hello, Willie Mays??????? </font>

Could you elaborate on that? Was there sabot material left in the barrel? The history channel Tiger show has a lot of Tigers firing and all of them have surprisingly low firing signature. Hm, I should make mpegs from all that stuff. (Especially on the turn rate footage to annoy the hell out of those people who think the CMBB turn rates are in any way accurate...) </font>