rexford

Spring 1942 German firing tests against T34 armor suggest that 40mm to 53mm high-hardness plates would resist hits by 37mm AP like the plates were made of medium hardness armor but the effective resistance would be 26% higher. Thus, when 37mm AP hits the 45mm at 40 degree side hull of a T34 the armor resistance would be calculated using the standard slope multipliers but the result would be multiplied by 1.26. So the 45mm flat area on the T34 mantlet would resist 37mm AP hits like 57mm of medium hardness rolled plate. The firing test results with 50mm AP do not result in clearcut results for hits on the 45mm at 40 degree side hull, since the majority of the hit angles vary from 55 to 65 degrees from vertical and the two hits at 40 degrees appear to be shatter gap failures due to uncapped 50mm AP. Two 50mm Pak 38 uncapped AP hits at 100m against 40.8mm armor at 40 degrees resulted in "durchschuss kleine als Kaliber glatt" results, which we think are partial penetrations. The odd thing is that the same rounds fully penetrated 42.1mm plate at 65 degrees at the same range, so why two failures against 40.8mm at 40 degrees? Are there any combat or firing test results that would add to the above German test results for 50mm Pak 38 attack on the side of a T34? Jentz has something which suggests a 600m to 700m penetration range for 50mm L60 against the T34 side, but additional results would provide a better foundation for penetration models. Thanks. Lorrin

Going through 26 firing test results against Tiger front, side and rear armor rolled plates (nothing against cast mantlet), came to conclusion that Tiger armor averaged 5% more effective thickness than 60mm, 80mm and 100mm design specifications. So, average effective resistance (before slope effect) of Tiger 60mm design spec plates is 63mm, 80mm design spec plates resist like 84mm on average and 100mm design spec armor resists like a 105mm plate. The above averages take into account true average thickness of plates (which is about 2% above 60mm, 80mm and 100mm) and actual ballistic resistance from Allied firing tests. The Allied firing tests used 6 pdr, 17 pdr, 75mm, 76mm and 90mm guns and ammunition. Tiger armor, which probably wasn't as mass produced as other panzers, appears to have averaged slightly better resistance characteristics than Panther, PzKpfw III and PzKpfw IVH armor. The Tiger armor resistance averaged 5% more than the design spec thickness but varied according to a bell shaped statistical distribution curve (most results bunched near average but some well above and some well below average).

Currently analyzing German spring '42 firing tests against T34 armor with 37mm and 50mm anti-tank guns, and came across following terms: Durchschuss kleine als Kaliber glatt Durchschuss Glatt Typing this at library without benefit of report so above is what I remember. Also came across an abbreviation term "oM" which I assume is a failure from some of the results but can't be sure. Would appreciate technical translation of above terms. Thanks.

If CMAK uses two penetration stats for each gun, then the 75mm APCBC penetration ranges against 80mm face-hardened and 80mm homogeneous should be radically different. Tiger has 82mm homogeneous side armor, PzKpfw IVG has 30mm/50mm front hull which probably resists like about 90mm face-hardened in CMAK on the driver plate (slope of about 10 degrees from vertical contributes to the 90mm effective resistance).

My understanding is that both CMBB and CMAK use two sets of penetration data for each Allied or Russian gun, homogeneous and face-hardened armor stats. And the games differentiate targets by armor type. So Tiger is homogeneous armor. PzKpfw IIIG, IIIJ, IIIH, IIIM, IIIN, IIIL are mostly face-hardened, as is PzKpfw IVF2,G,H and a good share of the J. Panther D has face-hardened hull all around, Panther A early models thru September 1943 have face-hardened front lower hull and side hull. StuG IIIF and IIIG is mostly face-hardened. British firing tests and combat reports support the conclusion that when a 32mm face-hardened plate was bolted to a 30mm face-hardened plate they resisted like a single face-hardened plate with 69mm thickness. So Russian 76.2mm APBC from a T34 or a field gun would penetrate the driver plate on PzKpfw IIIH on half the hits at 750m, and defeat the armor on one-fourth of the hits at 950m, when the gun barrel was aimed directly at the front hull. And the 30mm/50mm face-hardened plates-in-contact combo on the front of PzKpfw IVG and StuG IIIG would resist Russian 76.2mm APBC hits like more than 80mm face-hardened. U.S. firing tests found that the 30mm/50mm on the front of PzKpfw IVG's resisted like more than a single 80mm plate. While some have questioned the face-hardened plates in contact theory and conclusions, combat and firing test data supports the theory.

Suggest that you surround a Tiger at 100m or so with several Stuarts and see if they penetrate the side armor. I matched up a single Tiger against ten M5 Stuarts at 50m to 200m range, and the best result the 37mm APCBC got was a side partial penetration at 60m or so. StuG III's carry face-hardened armor so 37mm AP will penetrate much less face-hardened armor than homogeneous. However, a panzer with 50mm of face-hardened armor is not going to do too well against 37mm AP at close range due to too thin an armor plate. By the time Tigers appeared in Nord Afrika Stuarts should be firing alot of 37mm APCBC, which should have less than 82mm homogeneous penetration at 100m. The April 1943 Stuart data in CMAK shows APCBC penetrating 88mm at 100m, which appears to be too high for either homogeneous or face-hardened armor performance. They should take another look at the 37mm APCBC stats, both the penetration figures and the rate at which the shot loses penetration (penetration looks to high at close range and seems to fall off too fast). U.S. data for 37mm APCBC shows 78mm at 100 and 59mm at 1000m for homogeneous penetration (1000m penetration is 75.6% of 100m figure), CMAK has 88mm at 100m and 58mm at 1000m (1000m pen is 65.9% of 100m data). [ January 20, 2004, 06:40 AM: Message edited by: rexford ]

Since the majority of the panzers met in North Africa carried face-hardened armor, CMAK presents face-hardened penetration stats for many Allied weapons while CMBB showed the homogeneous armor figures (although many panzers in Russia also used face-hardened armor, such as PzKpfw III, PzKpfw IV, early Panther D and A, StuG III, etc.). 75mm APCBC fired by Shermans penetrates much more face-hardened armor at 100m than homogeneous because: 1. armor piercing cap assists in defeat of face-hardened armor by protecting projectile nose from shatter 2. armor-piercing cap absorbs energy against homogeneous armor and doesn't do much towards defeating that type of plate Face-hardened armor on panzers typically has a thin surface layer that is very hard, 450 to 600 Brinell Hardness. The armor defeats hits by breaking up the nose of the round, and if enough of the ammo survives and gets through the face-hardened layer the plate is gone-so. Armor piercing caps help to keep the nose intact, which is bad for face-hard armor. Homogeneous armor (240 to 300 Brinell Hardness is typical, occasionally up to 340 Brinell as on Tiger side) is defeated when a round strikes and has enough energy to push the relatively soft armor out of the way. Armor piercing caps take away from homogeneous penetration. U.S. 75mm M72 uncapped solid shot AP penetrates much more homogeneous armor than 75mm APCBC because it doesn't have an armor piercing cap, and doesn't have an HE burster cavity which weakens the APCBC rounds. Against face-hardened armor, 75mm APCBC is better than 75mm AP. American stats for U.S. 37mm AP and APCBC ammo show: 37mm APCBC fired at 2900 fps 78mm homogeneous at 100m 73mm face-hardened at 100m 37mm AP fired at 2900 fps 89mm homogeneous at 100m 65mm face-hardened at 100m American 75mm AP and APCBC: 75mm APCBC fired at 2030 fps 88mm homogeneous at 100m 102mm face-hardened at 100m 75mm AP fired at 2030 fps 109mm homogeneous at 100m 91mm face-hardened at 100m Since 75mm AP does not have a ballistic windscreen but has a somewhat blunt nose shape, APCBC rounds lose velocity slower than AP. U.S. 75mm AP also suffered from a tendency to shatter and had inconsistent powder charges which lead to accuracy problems. British used German 75mm APC rounds, Americans eventually bored HE burster cavities in 75mm AP rounds and re-used them as APCBC.

The Hetzer is quite vulnerable to many hits, including front hits on the lower hull armor. A Sherman 75mm APCBC hit that strikes the street pavement in front of a Hetzer and bounces up might pierce the front lower hull armor, and I think I read of such a case somewhere. The front lower hull armor on Hetzer is 60mm at 40 degrees from vertical, which is an easy mark for U.S. 76mm APCBC. If there is a quality factor less than 1.00 than Sherman 75mm APCBC would have a chance at close range. The side armor is very thin and an oblique hit that strikes the side armor might find its way through. The Hetzer front is so narrow that many shots which would land on the front armor of a Tiger or Panther hit the side plate on Hetzer. The upper side armor is 20mm at 40 degrees from vertical. Hitting that armor with a shot 20 degrees from the hull facing (70 degrees from side perpendicular) could still penetrate the 20mm armor even though the combined angle is 75 degrees from vertical. Hetzer is vulnerable in many situations where a full sized tank would not be, and they have to be used carefully or they can be lost very quickly. City streets are good, with rubble or ground in front of the front lower hull is great, out in the open facing M10's and easy eights and M36's is not so safe.

In the next few days I'll post an example of how the iterative method works. Oue book provides a simpler way to estimate velocity, where the equation is: velocity = muzzle velocity x 2.718282 raised to the following power ("meters range" x 0.7 x "K") The above equation works for rounds where the penetration is proportional to velocity raised to 1.43 power, which the equation does work for Russian flat nose windscreen capped APBC ammo. The thing about Russian APBC is that is follows an odd curve for penetration-vs-velocity against homogeneous armor, but lines up well with the penetration = velocity raised to 1.43 power against face-hardened armor, and the face-hardened penetration curves are what we used for APBC "K" figures. We analyzed the "K" factors for a wide spectrum of WW II rounds based on firing tables and ballistic documents, penetration curves and analysis using a trajectory computer program (BASIC language) that uses the iterative method. The results match the firing tables reasonably well. Lorrin [ January 16, 2004, 07:47 AM: Message edited by: rexford ]

Based on feedback and additional research following is final version of article on T34 glacis thickness variations: IMPACT OF VARYING T34 GLACIS THICKNESS ON GERMAN 75mm APCBC PENETRATION RANGES Info on T34 glacis thickness suggests a range from 42mm to 53mm, based on Jeff Duquette's measurement, German plate thickness range used in firing trials against T34 like armor and other info. Following are estimated penetration ranges against T34 glacis if thickness is in 42mm-53mm range. Guess after reviewing distribution of the limited sample of actual measurements in our possession is that design thickness of 45mm was most common thickness encountered and thicknesses under 45mm were much less common (most thickness specs allow no unders but do permit over thicknesses). EFFECTIVE RESISTANCE OF T34 GLACIS DUE TO VARIATIONS IN PLATE THICKNESS Glacis..Effect...Penetration Ranges (m) Thick...Thick...75L43...75L46...75L48 42.............84.....2008....2412......2088 43.............87.....1861....2266......1941 44.............90.....1720....2125......1800 45.............93.....1584....1988......1664 46.............96.....1451....1856......1531 47.............99.....1323....1728......1403 48...........103.....1158....1563......1238 49...........106.....1038....1443......1118 50...........109.......922....1327......1002 51...........112.......809....1214........889 52...........116.......663....1067........743 53...........119.......556......961........636 ========================================================= Notes: Effective thickness after high hardness plate converted to good quality vertical 240 Brinell armor using slope effects and armor resistance adjustments. Germans use 42mm to 53mm plates when they fire on T34-like armor. Three 45mm design thickness plates on SU 100 were measured at 60mm (front lower hull), 42mm (superstructure side) and 50mm (superstructure side). Battle reports have 75L46 Pak 40 penetrating T34 glacis to 1000m (matches 53mm glacis range) and 75L43 penetrating to 1600m max (matches 45mm glacis thickness). Jeff Duquette measures T34 glacis at 50mm-55mm, Su 100 measured at 42mm-60mm, other measurements in 45mm to 47mm range, which supports second note with exception of 60mm thickness. ========================================================= The above penetration ranges are based on average performance of the APCBC projectiles, level ground, no projectile descent angle and a somewhat pessimistic view of how the high hardness plate would perform. The ranges can vary widely based on variations from the assumed ammo and armor characteristics. The impact of variations in the assumed ground, armor and ammo conditions can be significant: 1. A 2 degree ground tilt can increase armor resistance by 11% or decrease it by 7% 2. German 75mm APCBC rounds for the abovenoted guns will be descending at about 1 degrees at 1600m, which decreases the assumed resistance by about -3.5% 3. German quality control tests showed that the velocity spread from worst to best ammo to defeat a given thickness could vary by 24%, which means that the best rounds could penetrate 16% more than average and the worst could penetrate 15% less Pavel noted on the Yahoo! Tankers site that Hetzer hits on the front hull glacis plate of T34/85 tanks failed to penetrate at very close range (early 1945), a result which at first was difficult to explain. An explanation for the failures against the T34/85 glacis might be related to some combination of the following possibilities: glacis plates above 45mm thickness slight upward tilt to ground increasing impact angle above average Russian armor below average ammo some hits landed on the 75mm thick driver hatch (two T34/85 driver hatch castings measured at 75mm, and T34/76 hatch on Jeff Duquette photo is about 40% thicker than 53mm glacis plate for 74m) 75mm L48 APCBC penetration at 100m with a 15% decrease from average would equal 115mm of vertical plate, which could be matched or exceeded by 50mm glacis thickness with a combination of ground tilt and above average penetration resistance. American tests of T34/85 plate from tanks found in the Berlin ruins showed that the armor varied in quality from poor to excellent. The question has been raised as to what impact above average glacis plates would have on T34 tank weight. Each additional mm of thickness adds about 55.5 pounds (25 kg), so a 5mm increase would add 278 pounds (126 kg) and 8mm would add 444 pounds (201 kg). So the bottom line is that German penetration ranges against T34 armor could and did vary widely based on expected variations in conditions, armor and projectiles.

Velocity loss per second is equal to: air density x velocity squared x diameter squared x form factor x drag coefficient divided by projectile weight A form factor is needed because actual projectiles are rarely the same as the rounds used to generate the drag coefficient vs velocity curves. Major changes encountered include nose length relative to diameter, secant ogives instead of tangent ogives and whether ammo has a boat tail (standard Type 1 uncapped AP round used for curves has a flat base while many AP rounds used during WW II has a boat tail which reduced air resistance). A really rough estimate for velocity at range can be made using small increments of time (like 0.1 seconds or less) and going through iterations. A. Initial velocity at muzzle - velocity loss per second at 0m times 0.1 second = first estimate for 0.1 seconds. B. Since initial estimate used muzzle velocity and velocity at end of 0.1 seconds is lower, must use average velocity within interval (basedmuzzle velo plus first estimate at 0.1 sec.) C. Use average velocity for first 0.1 seconds from step B. to recalculate velocity loss within interval. D. Keep going until changes are acceptably small There is a computer program that automatically does all of this, generated by William Jurens and included with his article TERMINAL BALLISTICS FOR THE MICRO-COMPUTER which was published in Warships International. My copy is buried in boxes in a storage shed or I would offer to share some copies.

German 50mm AP and APC and Russian AP rounds follow a relationship where penetration is proportional to velocity raised to 1.43 power, or velocity is proportional to penetration raised to 0.7 power. This comes from the DeMarre equation. Find the 0m penetration for each of the AP and APC rounds, divide the penetration at range by the 0m figure, raise the result to the 0.7 power and multiply by the muzzle velocity. That will be the velocity at range. Russian flat nose APBC rounds follow a more complicated equation that can be found in our book.

The posted penetration ranges are based on average performance of the APCBC projectiles, level ground, no projectile descent angle and a somewhat pessimistic view of how the high hardness plate would perform. The ranges can vary widely based on variations from the assumed ammo and armor characteristics. The impact of variations in the assumed ground, armor and ammo conditions can be significant. 1. A 2 degree ground tilt can increase armor resistance by 11% or decrease it by 7% 2. German 75mm APCBC rounds for the abovenoted guns will be descending at about 1 degrees at 1600m, which decreases the assumed resistance by about -3.5% 3. German quality control tests showed that the velocity spread from worst to best ammo to defeat a given thickness could vary by 24%, which means that the best rounds could penetrate 16% more than average and the worst could penetrate 15% less Pavel noted on the Yahoo! Tankers site that Hetzer hits on the front hull glacis plate of T34/85 tanks failed to penetrate at very close range (early 1945), a result which at first was difficult to explain. If the T34/85 tanks carried glacis plates above 45mm thickness, were on a slight upward tilt and the Hetzers were firing below average ammo it is reasonable for the 75mm APCBC hits to bounce. 75mm L48 APCBC penetration at 100m with a 15% decrease from average would equal 115mm of vertical plate, which could be matched or exceeded by 50mm glacis thickness with a combination of ground tilt and above average penetration resistance. American tests of T34/85 plate from tanks found in the Berlin ruins showed that the armor varied in quality from poor to excellent. The question has been raised as to what impact above average glacis plates would have on T34 tank weight. Each additional mm of thickness adds about 55.5 pounds (25 kg), so a 5mm increase would add 278 pounds (126 kg) and 8mm would add 444 pounds (201 kg). So the bottom line is that German penetration ranges against T34 armor could and did vary widely based on expected variations in conditions, armor and projectiles.

Muzzle velocities for German 75mm guns: 75L43 APCBC: 740 m/s 75L46 APCBC: 792 m/s 75L48 APCBC: 750 m/s

Info on T34 glacis thickness suggests a range from 42mm to 53mm, based on Jeff Duquette's measurement, German plate thickness range used in firing trials against T34 like armor and other info. SU 100 front lower plate, which was 45mm design spec, actually measured at 60mm by Allies. Following are estimated penetration ranges against T34 glacis if thickness is in 42mm-53mm range. Guess is that plate thicknesses under 45mm were relatively rare (most thickness specs allow no unders but do permit over thicknesses). Effective Resistance of T34 Glacis Due to Variations in Plate Thickness Glacis..Effect...Penetration Ranges (m) Thick...Thick...75L43...75L46...75L48 42......84......2008....2412....2088 43......87......1861....2266....1941 44......90......1720....2125....1800 45......93......1584....1988....1664 46......96......1451....1856....1531 47......99......1323....1728....1403 48......103.....1158....1563....1238 49......106.....1038....1443....1118 50......109.....922.....1327....1002 51......112.....809.....1214....889 52......116.....663.....1067....743 53......119.....556.....961.....636 Notes: Effective thickness after high hardness plate converted to good quality vertical 240 Brinell armor Germans use 42mm to 53mm plates when they fire on T34-like armor Battle reports have 75L46 Pak 40 penetrating to 1000m (matches 53mm glacis range) and 75L46 penetrating to 1600m max (matches 45mm glacis thickness) Jeff Duquette measures T34 glacis at 50mm-55mm, other measurements in 45mm to 47mm range, which supports second note [ January 13, 2004, 05:43 PM: Message edited by: rexford ]

Vasiliy said they included U.S. 75mm in tests, which could be questionable I guess.

Jason, You are so wrong and continue to either ignore or fail to understand a simple statement I made which is supported by fact. Panthers were built with 50mm and 60mm front lower hulls. At Isigny the U.S. 76mm APCBC failed against the 60mm lower hull front at close range, and so did 76mm HVAP on 2 of 3 hits at close range. Turns out the 60mm design thickness was actually 67mm on one of the Panthers where they measured. When a Panther had a 50mm front lower hull, as many did in the Normandy battles, then an M10 hit with APCBC would penetrate at close to medium range. Continue to ignore the above facts and I'll just have to ignore your garbage in the future. U.S. Navy tests show that 76mm APCBC could shatter fail against 97mm of rolled homogeneous armor at close to the muzzle velocity, which suggests that hits on the Panther mantlet at 200 yards could fail in certain circumstances. Now that I think about it I'am not going to continue to repeat the same stuff in response to your nonsense, and argue with you. If you don't want to face facts, that's your problem. Lorrin [ January 11, 2004, 11:34 PM: Message edited by: rexford ]

"The September 1943 test is the more significant one to be analysed. Ignore the Fleischer excerpt, the book is 1989, it appears he has a 1997 edition out and re-examining the book from the Library it appears to be penetration estimates based on the captured tank T34/85 tank." Not true. The April 1943 test is the more significant one because it showed actual penetration ranges that make sense, while the September 1943 test results are highly questionable and are difficult to explain (my explanations are not universally accepted). Lorrin

Here is a post I just added to the Matrix Games web site: Vasiliy Fofanov posted results of a September 1943 firing test by Russians against the 82mm side armor on a Tiger tank: 76.2mm guns fail at 100m and 500m with 0 and 30 degree side angles And at 100m and 500m to 600m: U.S. 57mm anti-tank gun fails U.S. 75mm fails Russian 85mm fails German 75mm Pak 40 fails It is further noted in a post by karl smasher that 75mm Pak 40 routinely defeated 80mm to 85mm of Russian plate during virtual test bench trials at a simulated range of 600m: "Saenko, Melnikov, Satel Verified: Ustinov, Voronov September 11, 1943" PAK 40: "In spite of the fact, that this captured artillery system reliably penetrates the armor plates of 80mm and 85mm thickness from the testbench at the virtual distance of 600m, during the firing at "Tiger" tank by two pieces with 30 AP rounds each from a distance of 600-500m no full penetrations of side armor were obtained." The above suggests to me that the armor was attacked at an angle. The 75mm Pak 40 APCBC would defeat 130mm on half the hits at 600m, so 85mm plates would only be a challenging target at an angle. If Russians used face-hardened, high hardness or flawed armor, the impact angle of 75mm Pak 40 against 85mm plate would be about 44 degrees. Now, if Tiger 82mm resisted like 92mm due to above average resistance (in tests against U.S. 90mm APCBC, Tiger 82mm resisted like 89mm effective), and it was more resistance than Russian test plate, hits at 44 degrees would routinely fail. So Tiger defeat of all rounds might be due to combination of above-average resistance of 82mm plates and lowered resistance of Russian test plates that were used to set test angles for other than 76.2mm ammo. Analysis of Allied firing tests against five captured early production Tigers indicates that Tiger 82mm plates averaged 3.3% more resistance than good quality American plate, with a maximum advantage of 9% over U.S. armor. The following was posted by karl smasher on the Combat Mission Barbarossa to Berlin site, and in this case shatter appears to be the culprit: " In reply to the the 85mm results, do you have the German report of firing trials using a captured T34/85 tested April-1944(wolfgang Fleischer book "WEAPONS TESTING") at Kummersdorf. The T34/85 failed against front hull and turret at 500m0degrees. Penetrations by 85mm were obtained against the side armor of the Tiger at 500m@0degrees by 85mm BR-365K. Note BR-365 (flat nose) failed at all ranges, rounds rounds broke up. It mentions BR-365K was more effective against the vertical tiger armor than the other flat 85mm nose rounds. Again these rounds tested were all captured from the inside the tank." [ January 09, 2004, 09:11 PM: Message edited by: rexford ]

"7) 3-inch Gun, M5, mounted on Motor Carriage, M10 a) APC M62, w/BDF M66A1 will not penetrate front glacis slope plate at 200 yards. Will penetrate gun mantlet at 200 yards and penetrate sides and rear of the 'Panther' Tank up to 1500 yards. AP M79 will not penetrate the front slope plate or the mantlet at 200 yards. It holds no advantage over APC M62 ammunition w/BDF M66A1. So the M79 round does not penetrate the mantlet at 200 meters." The AP M79 outpenetrates the U.S. 76mm APCBC by about 25mm at 200 yards and does not have an HE burster so the failure cannot be related to base HE detonation. Why does 3" M79 AP fail against the Panther mantlet at 200 yards but the 76mm M62 APCBC with less penetration succeeds? Why does 76mm M62 APCBC fail against the Panther mantlet beyond 200 yards when it has 100mm rolled armor penetration at 1250m? And don't say the rounded mantlet is superior to a flat plate cause the British tests say it ain't so! [ January 09, 2004, 07:55 AM: Message edited by: rexford ]

"There ARE failures in these tests from the base HE going off prematurely by the way. I think a better question is why is penetration of the cast mantlet such a problem? The only shatter data you show is point blank range? How is that a 'gap'?" ============================================= Base HE burster going off was problem with 90mm APCBC, not 76mm. Penetration of the Panther cast rounded mantlet was not a problem as I previously showed by reference to British firing tests against Panther mantlet. If 6 pdr APCBC penetrates Panther mantlet well beyond 500m then the U.S. 76mm APCBC should, too. The British firing tests show that it is silly to assume that a rounded mantlet has superior resistance qualities, no truth to that at all. Penetration of the rounded cast Panther mantlet may have been a problem for 76mm APCBC due to shatter gap tendencies. It's a shatter gap because the tests used velocities above and below the muzzle velocity and there is a range of velocities where it fails surrounded by velocities where it succeeds. A gap in the penetration results. When a person quotes Wa Pruf penetration range estimates as proof of anything they should keep in mind that those figures were usually calculated from available data, and assume all sorts of impact angles. The penetration data is sometimes wildly inaccurate, and the armor may or may not be adjusted for cast armor deficiency, high hardness problems, poor quality or whatever. It was also a standard procedure to use a 30 degree side angle on many of the penetration range calculations, or to assume a 30 degree hit on a rounded piece of armor. One calculation has Panther hits on the T34/85 glacis failing beyond 800m. In other words, Wa Pruf penetration range data proves nothing and is sometimes inconsistent with actual firing tests. Lorrin [ January 09, 2004, 07:50 AM: Message edited by: rexford ]

German data and production drawings on the Panther mantlet show a maximum thickness of 100mm. The armor is cast so will be inferior to rolled homogeneous armor. Theories aside, British firing tests with a variety of weapons and ammunition show that the 100mm Panther mantlet casting resists penetration like a lower thickness of rolled homogeneous armor when it is hit around the apex (center area). Web site presentations of penetration ranges are often based on paper comparisons of penetration data to armor resistance at some unstated impact angle, and who knows what data was used. Actual firing tests against the Panther mantlet show that it was inferior to 100mm rolled homogeneous armor around the center point. The American firing tests showed Panther mantlet penetrations at 200 yards max range by 76mm APCBC, where ammo penetrates about 123mm vertical. Hits at 15 degrees impact angle would be resisted by about 101mm vertical resistance, so why the 200 yard max range? My theory is that shatter gap may have played a part, since the ammo failed in U.S. Navy tests when it hit 3.82" plate at 20 degrees and a velocity pretty close to muzzle velocity even though it should have easily penetrated. Lorrin

"Moreover, note that the report specifically states that some of the guns tested were found to be sufficient to penetrate the corresponding thickness test plate, but still failed on the Tiger's side, so this shatter gap was suspiciously selective." Shatter gap may be a function of the interplay of projectile and armor, and it is possible that the characteristics of the Tiger armor (hardness, ductility, strain hardening, inertial resistance, ballistic resistance, etc.) were such that the armor promoted shatter while Russian armor plate did not. Suspicious is not the word to use here since the difference can be explained.

Based on what we've discussed there is no inconsistency between 85mm penetrations of Tiger armor at 1000m and 1500-2000m and failures at 100m and 600m, if shatter gap, exceptional armor and possible inferior ammo is considered.

The report broken into parts is in the following long thread http://www.battlefront.com/cgi-bin/bbs/ultimatebb.cgi?ubb=get_topic;f=23;t=006743;p=2 I'm' surprised you forgot(or lost) the report because later in the thread you reply to many of Jonh Walter's posts. Saenko, Melnikov, Satel Verified: Ustinov, Voronov September 11, 1943" PAK 40: "In spite of the fact, that this captured artillery system reliably penetrates the armor plates of 80mm and 85mm thickness from the testbench at the virtual distance of 600m, during the firing at "Tiger" tank by two pieces with 30 AP rounds each from a distance of 600-500m no full penetrations of side armor were obtained." About the above excerpt, did the soviet use high- hardness cast armor as test plate when testing their guns?. The report above has Pak 40 reliably penetrating their own 85mm testing plate, but failing on RHA armor on a Tiger side. Would you put this down to shatter gap and/or higher quality tiger plate compared to there own test plate. The data you have for 85mm and 57mm guns may come from high quality 'test rounds' while the September test are production ammo what the front troops got. Also the shatter gap against Tiger armor seems be a big issue, not just with Russian as shown in British and U.S Tests. In reply to the the 85mm results, do you have the German report of firing trials using a captured T34/85 tested April-1944(wolfgang Fleischer book "WEAPONS TESTING") at Kummersdorf. The T34/85 failed against front hull and turret at 500m0degrees. Penetrations by 85mm were obtained against the side armor of the Tiger at 500m@0degrees by 85mm BR-365K. Note BR-365 (flat nose) failed at all ranges, rounds rounds broke up. It mentions BR-365K was more effective against the vertical tiger armor than the other flat 85mm nose rounds. Again these rounds tested were all captured from the inside the tank. Eiter high quality 'test rounds' that are not availbe to front line troops, or 85mm BR-365P. and 57mm gun is odd, or is it british 6lb or US 57mm. </font>