rexford

122mm APBC penetrates Panther glacis at 1500m withn good quality armor, 2500m+ with 0.83 quality. 122mm AP fails to penerate good quality Panther glacis but can sneak in 700m pentrations if quality is poor. At Kubinka, 122mm APBC easily penetrates Panther glacis at 2500m. We have U.S. test data for 122mm APBC and good quality Panther glacis with 85mm armor at 55° would be penetrated at 1500m, based on U.S. tests. This supports Russian combat reports posted on Russian Battlefield site. Following is from info posted by Valera Potapov on his site long ago and not presently available: -------------------------------------------- 76.2mm ZIS-3 gun firing tests against IS tank at 500-600 meters resulted in partial penetrations from all sides, and although there were few complete penetration there was major splintering and fragmentation inside the tank. This explains the losses of IS-85 and IS-122 tanks in winter-spring of 1944. ----------------------------------------- My data shows 76.2mm penetration for complete defeat is about 73mm at that range, and IS armor is 90mm minimum. IS-2 with 122mm gun reported to have 1200m penetration range against Tiger I front hull, which may have been with AP rounds. Our book lists 139mm penetration at 1250m for 122mm AP, and 144mm for 122mm APBC. Seems like range would have been further, although Russian Battlefield has 11% lower penetration for 122mm AP.

At Kubinka, 100mm and 122mm rounds penetrate captured Tiger II turret front at 1000m to 1500m range. Turret front armor has quality of about 0.85. If 122mm AP hits Tiger 100mm at 10° driver plate at 45° lat angle (oblique hit) and 100m, armor resistance is close enough to round penetration to defeat hit or cause it to shatter fail. If 122mm AP hits 100mm at 25° nose armor on Tiger at 45° lat angle, armor resistance is greater than penetration at 100m. The story is possible of Tiger I beating 122mm hit at very close range. 122mm APBC would change story since it has much lower slope effects.

The 122mm APBC round fired by IS-2 could penetrate a good quality Panther glacis at 1500m, and a flawed glacis at over 2500m. This is based on tests and combat experience. The 122mm AP round bounced at all ranges against good quality Panther glacis, and might penetrate a flawed glacis at up to 700m. 122mm penetrates Panther 100mm cast mantlet to really distant ranges. Panther 75mm will not penetrate IS-2m glacis at any range, but will penetrate 100mm turret and mantlet armor at really far ranges. Panther has more APCBC rounds than IS-2m carries AP or APBC. 10 armor piercing rounds don't go far. Combine that with low rate of fire and IS tanks have problems going toe to toe with Panther, and maybe even a PzKpfw IVH. Regarding IS-2/2m vs Panther, Russians were very concerned when initial combats showed 122mm AP to be near useless against Panther glacis. I did not mean to say the Tank vs Tank combats 'tween Panther and IS-2 were everyday affairs, but they appear to have occurred on other than a rare occasion. Back in the 1980's I bought a computer wargame with historical scenario's and one of the battles had a large Panther unit attacking an advancing IS-2m group. Panthers won. Combat directives may have said that IS-2 tanks were to concentrate on infantry defensive positions, but just like the Shermans that were directed to attack infantry and leave tank fighting to others (M10 units), IS tanks and Shermans would get drawn into tank combat when defensive positions were reinforced or counter attacks were made. Despite combat directives to the contrary, how many Shermans ended up fighting Panthers and PzKpfw IV in France?

A Puma armored car could probably have destroyed a T34/85 at 200m with a side shot, and blocked the road by busting a T34/85 track. Good point and valuable story, tanks are tanks but good crews can find ways to use em to great advantage. There are stories on The Russian Battlefield site where T34/85's kicked Tiger II butt, due to a combination of smart positions, holding fire till the last minute, initially firing from select positions to get the targets to turn vulnerable armor to the main positions, and T34/85 mobility. There is also a story on The Russian Battlefield where two 75mm armed Shermans would routinely K-O Tigers in Russia using a neat technique. First Sherman aims at and knocks out left track and when moving Tiger rotates after track breakage, second Sherman is perfectly positioned for a flank shot. They planned beforehand which track they would aim for and positioned the other Sherman accordingly. Innovative technique defeats superior armor and weaponry.

Panther did alot that T34/85 did not do, like survive 75L48 hits on glacis at 1400m. T34/85 frontal armor is not very effective against 75L48, 75L70, 76.2L51.5, 88L56, 88L71, etc. Panther glacis held 88L71 to 600m penetration range in Russian test. T34/85 would need over 6000m. Yes, 6000+ meters to stop 88L71 hit. Panther firing system allowed hits at 2000m to 3000m, due to gun velocity and stability, and opticks. Next to 76mm HVAP, Panther gun probably has lowest scatter of any WW II weapon, even lower than Tiger 88L56 which impressed British during tests of captured kat. Panther designed for long range stand-off kills, T34/85 for mobile rip throughs.

There were quite a few combats between Panthers and IS-2's, and IS-2 was designed to combat Panther. 122mm gun was chosen in part because it was more effective against Panther armor in tests. Better HE was the other reason, 122mm packs more wallop than 100mm. Early combats between Panther and IS-2 showed that 122mm AP would not penetrate Panther glacis, which upset Russian designers. Several combats later, some penetrations were obtained at less than 700m with 122mm AP, which was still was adequate. Use of 122mm APBC round resulted in 1500m penetration range against non-flawed Panther glacis, and penetrations beyond 2500m were possible against flawed glacis (please note that Panther glacis quality is not a constant but varies, and about half would have 1.00 multiplier instead of 0.85). Russian Battlefield notes that IS-2 hits beyond 1200m took an experienced crew, which places things in perspective and gives Panther an advantage. Panther versus IS-2 combat did take place and is a valid comparison. Even if Russian tanks did carry more HE than AP, and IS-2 tank assaults would initially be against infantry held positions, Panthers could be called upon to close the gap and eliminate the intruders. Which brings up the final point, IS-2 tanks carried 10 AP type rounds versus how many for Panthers? In a battle where IS tanks could not be readily re-supplied, such as a mobile breakthrough with German counterattack, would slow rate of fire and limited anti-tank ammo be a detriment? How good are 122mm HE rounds against Panther?

If I might be allowed the liberty of short summaries, based on a preponderance of anecdotal, experience based and scientific documentation: 1. 2 second rule as "xtreme range" is not clearly defined as to intent, since hits have obviously occurred beyond that range with bracketing. Does 2 seconds mean no hits possible on first or following tries, or less than 5% first shot accuracy? Xtreme range does not seem useful as a rule of thumb unless it is tied to something else. 2. Fair accuracy is possible beyond 2 second flight time with bracketing, range finders and outside observers directing fire, along with defensive use of range cards (landmark use or stakes in the ground with known ranges to each). 3. If hit system assumes adequate gun sight visibility, then non-German accuracy might be due for decreases under conditions where sights are not as adequate: A. decreased light (early morning and early evening, overcast, fog that limits sight range or blocks out the sun, etc.) B. longer ranges where spotting tracers or fall of shot may be difficult and is needed to improve accuracy of follow-up shots C. spotting camouflaged vehicles and dug-in guns (maybe), where clarity and distinction between colors and objects is important. D. longer ranges where clarity is needed to aim at center of target in order to gain maximum hits on target, as opposed to fuzzy images that may result in aim at bottom, top or side edge of target. Working this into a system varies from straightforward to somewhat complex (range for reduced light during early morning or evening may change with hour, 500m at sunrise, 1000m 30 minutes later, etc). The first step is to define the conditions where sighting systems may be less than adequate, then one can start assessing how much of a difference may result, whether impact is worth the work and how should the darn thing be addressed if it is deemed to be worthwhile. The above approach recognizes some of the limits of Allied and Russian sights and uses German optics as the "adequate" basis. A T34 can still hit at 1500m with a decent crew and a clearly defined target, but at 2500m with an overcast or prior to sunrise with a full moon, Tigers might see targets or follow-up shots that Shermans and IS-II's cannot. This is an attempt to summarize the previous discussions and is certainly not the last word on the subject.

Rereading the Eisenhower counters many of the faults that were supposedly found with the conclusions and methods, and suggests that others should read it again, too. Most of the discussions are not be tankers, they are OFFICERS, and many of them have considerable armor experience. Some were in armor since the beginnings in Tunisia. German sights are clearer, allow faster laying onto the target and work better in reduced light. Officers inspected the sights and came to these conclusions, not just "Tiger intimidated" tankers. The conclusions from the officers, many of whom were probably West Point trained with engineering courses under their belt, are in line with the posts on how Panther optics were better than U.S. (based on French study?). From my perspective, opinion is opinion but we are talking about experienced officers talking in a rational manner about German advantages in the field. Informed judgement and personal experience is what it appears to be instead of someone's opinion. Will the "faster laying" result in Germans never missing? No. Will clearer sights result in 50% hit probability on the first try at 3000 meters? No. At 500m with targets in the open, sight clarity, better sighting with overcast skies and ability to quickly see and lay on a target, are not that big a deal. Sighting advantages will not make up for turret traverse difficulties. German sighting advantages will show up against difficult to see targets, long range shots and when direct sunlight is minimal. So we are talking under specific conditions that are not likely to turn most CM battles around (due to range, clear skies and the way things work). In a shoot out at 2500 meters, Tigers might have a sighting advantage over M4A3's with 76mm guns. Since direct hits on the first shot at unlikely at that range, Tigers will use bracketting and the question then is whether better sight clarity is significant with bracketting (probably helps to see where shots land better, or to pick up the height as they pass target). So maybe Tigers and Panthers can see misses better and bring the brackets onto the target faster. Worth a few points on the accuracy meter, maybe. Our analysis of hit probability using bracketting shows less than 5% on first try and up to 30% or so after several shots, better sights might bring round onto target a few shots quicker at 2500m. How often does that occur in CM? If German sights have advantages, and many different sources suggest or support the theory, then the next step is how that results in accuracy improvements. Better sights will not improve first shot probability, but may bring bracketting attempts onto the target a little faster. We should note, when reviewing reports of 2000m to 2500m hits on the first few shots, that Germans may have layed out the approach routes on range cards and had the range estimates down to high accuracy. This is a distinct possibility given the defensive posture of the panzers late in the war. Acknowledging sight advantages, if one looks fairly at the support, feels advantages existed and judges it will make a difference, would be a nice touch. And would include something that seems to give the panzers an added boost on their long range shots. If some issue is felt to be important but cannot be precisely computed, or even roughly estimated, we would try to find some way to include it in a reasonable fashion. But couldn't the impact of better sights be roughly estimated based on improvements to bracketing corrections and getting the aim on the target center. And being able to see ill-defined targets with better clarity and speed. Sounds like something that can be quantified using order of magnitude estimates.

Just reread the entire "tankers talk" report on http://www.hitechcreations.com/ubb/Forum9/HTML/000686.html So many officers and tankers attest to superior German sights in the aforementioned report, reports comparing Panther and U.S. (?) sights testify to superior German sights, claimed superiority of German sights is consistent with scientific info presented on this thread. When so many different sources suggest the same thing or support other statements, it is worth further pursuit and consideration.

The last statement in my last post was tongue-in-cheek, and seems to have generated responses that equal or exceed mine in length. Subject is a touchy one, alright! What to do with optics questions is so subjective that it is probably impossible to please everyone.

Ridgeway's point is well taken and summarizes the two second rule business, tanks don't have much chance to hit on the first shot at 2 seconds flight time, and that is why bracketting is taught. With bracketing hits at 2500m will take several shots but they may come given overall weapon stability. It takes good sights to hit at 2500m, especially in overcast conditions without bright light. As was noted in a previous post, naval guns hit at far beyond 2 second flight time, try 30 seconds! But they use bracketing, and it would be interesting to read whether that 2 second rule considered bracketting. It is also difficult to face all that has been said about German optics superiority and deny its existence. While American tanker comparison in Europe hits on same conclusion as scientific fact (German sights better in low light conditions), and suggests that they tested under similar conditions, there is so much other anecdotal and published report data. Regarding the "how do we quantify gun sight advantages when it is basically unquantificable", BTS answered that. It is the same as hit % diff between 88L71 and 50L60, and between elite and average: think about how it would impact the results and how it fits into game system and input a modifier based on overall consideration. If better German sights are more effective during an overcast, they would boost hit %, as would the tiny little triangles for range estimation. But maybe it would be better to decrease % for sights that are inferior. Since CM does not use trajectory analysis and range estimation models for hit probability, results are not based on equations. So gun sight modifiers would fit in with everything else based on consideration of overall factors, wouldn't they? Does the opposition to German optics quality input into game mechanisms sound a little like a fear that the panzers will fight more effectively?

Question is complicated by main targets. T34 with 76.2mm penetrates about 75mm homogeneous armor at 500m, Panther 75mm penetrates about 170mm. Panther round is fired at 935 m/s, T34 at 680 m/s, so if everything else is equal Panther hits more often since faster rounds are less impacted by range estimation errors. Panther round also had one of the smallest dispersion patterns (scatter from shot to shot with constant aim). If T34 is firing at PzKpfw IVF2 or IVG with 76.2mm, there is probably enough penetration against their face-hardened frontal armor to knock them out at all practical ranges. PzKpfw IIIH (layered face-hardened armor) and PzKpfw IIIJ,L,M with spaced armor (20mm homogeneous a few inches in front of 50mm face-hardened) would be able to detonate 76.2mm burster between the plates. So 76.2mm can knock out a PzKpfw IVF2 or G at about the same ranges 75L43 can K-O T34, in frontal shoot outs. PzKpfw IVH (and later G models) has face-hardened armor hull armor and it can defeat a good share of 76.2mm hits. 76.2mm gun becomes less effective as German armor thickens. Panther 75mm can penetrate frontal armor on KV-I, T34, SU 85 and IS-2 at fairly long range and turret front/mantlet on IS-2m can be defeated at long range. But side armor on Panther leaves tank very vulnerable to 76.2mm hits. As targets change what was sufficient becomes inadequate. Tiger makes T34 with 76.2 gun close to what was considered "suicidal" ranges for side penetration attempts. The first Tiger combat with T34 was a shock because T34 were used to sitting outside German position and picking off panzers as they approached, due to longer effective range of 76.2mm gun. However, Mister T34 raised his hat when he met a Tiger (T34 turret ended up many yards from tank after 88 did its work).

88 Flak had much larger dispersion than Tiger I 88, probably due to shaking of the mount versus a nice heavy tank platform. 2 second rule seems to go out the window with Tiger I and Panther experience. American tankers note that German optics are superior to theirs in low light, like overcast. Now isn't it amazing that the actual fact is that German sights should be better in low light conditions, based on posts on this thread. Suggests that whatever American tankers did to actually compare sights, they hit the difference right on the head, which suggests direct comparison under overcast low light conditions. How to calculate hit % difference due to sights? How does one differentiate between an elite crew hit % and an average hit%? How does one compute hit % difference between 88L71 and 75L24? Since CM does not appear to compute hit % using trajectories, range estimation and dispersion, the system would seem to be open to subjective adjustment. Correct for sight qualityy by adjusting the curve till it seems right. German sights outshine others during low light and conditions that render targets difficult to pick up. This is highly specialized, isn't it? How often would the sight superiority show up in CM? Could T34 hit at 1500m with poor sights? This is basic question. Shermans with garbage sights can't hit very well beyond 500m or so, sights on roof hooked to gunner via linkages that get misaligned. 1500m accuracy by T34 suggests decent sights, doesn't it? That was 1942. Could T34 sights have deteriorated as war progressed, or have varied from one factory to another or one shipment to another. Maybe. Some reports on IS-2 say that it took an exceptional crew to hit beyond 1200m. Yet standard penetration range against Panther glacis is 1500m. Are German reports on penetration ranges realistic? German reports seem to coincide with American reports. Nothing beyond 3000m, but 2000m or more. Our book has 10 mph wind drift data for U.S. APCBC. 2.2m wind effect for 75mm L40. That's a miss if one aims at the center of just about anything. But the second shot corrects for the error in the first shot, so wind effect roughly disappears after the first shot. Same for sideways drift, which is also in the book. Estimates are fine, but the final judge of an equation is how well it fits the real thing.

We are now taking pre-order registration information for book sales in USA and Europe. Due to bureaucratic form filing, I cannot take orders through mail till July 10. USA, Canadian, Australian and other area sales info from Lorrin Bird at rexford179@cs.com Europe sales info from Frederic W. Erk at curator@musee-des-blindes.intranets.com

There is just as much reason to give credit to 2000m hits and American beliefs about German sights as there is to ignore it all. But there are so many reports of hits beyond 2000m by single Nashorn, or a few Tigers, and a single Panther using limited number of shots, that my view is that the extreme range limit is a good attempt to quantify a difficult issue, but may be too pessimistic. And as I pointed out for 2 pounder AP and Tiger 88, muzzle velocity alone does not determine extreme range with certainty. If American sights are poor in overcast conditions and U.S. tankers say German sights are better, doesn't this imply that: A. Americans are smart enough to test both sights under same conditions, which doesn't take a rocket science degree, just some intelligence B. Americans could compare sights under similar conditions, since overcast was common during time of year To assume that U.S. tankers would not have ability to figure out how to test things really assumes the worst. I give them credit for being able to figure things out using some logic. Read the Eisenhower report and see if it sounds like U.S. tankers had enough sense to test the sights for comparison purposes.

My comment on the two second rule was based on reports of hits well beyond the extreme range limit. German Tiger crews expected to hit by third shot at up to 1200m. Yet 1560m would be the extreme limit? The two second rule is not so simple to apply. 2 pounder AP has 2600 fps muzzle velocity while Tiger 88 has 2558 fps, so 2 pounder AP has longer extreme range? 2 pounder AP loses velocity much faster since it does not have windscreens and is much smaller. This results in a wickedly curved trajectory with increased shot error for a given range estimation error. Plus 2 pounder AP has much greater scatter than Tiger 88. Add to this fact that 2 pounder AP sights only go up to 1500 yards and round would be more impacted by crosswinds due to slower average velocity to target. American tankers in Europe reportedly had trouble seeing targets with reduced light, such as overcast conditions, and I imagine they tried German sights under same conditions and saw much more (or better). There are many ways tankers can compare sights without being scientists with degrees. I take all of this to mean American sights were inferior under specific conditions. Our book has data on drift and wind effect for a variety of WW II U.S. APCBC rounds. For a constant wind velocity and direction the first shot is impacted, the follow-up shots correct for wind and drift and it may become a non-factor. I am not trying to discredit two second rule, only show that combat reports exceed the extreme range limit quite often. If extreme range assumes crosswind (how many mph did they use), did they base estimate on analysis of typical wind velocities and directions. I work as an airport engineer and planner and have access to wind data for all major airports in U.S. as well as New York State. Calm winds are considered as 4 mph or less, and most airports have about 25% calms (going by memory). If tank is firing east to west, a percentage of winds will be facing or coming from behind firer. Appreciable crosswind on round is not always there. And if wind is blowing at constant speed, follow-up shots correct for wind and drift and mis-aim and other factors. This is how our book addressed drift and wind impacts, mostly a problem on first shot. Time of day has a big impact on winds, since winds usually start out low during early morning and pick up as day goes by, peaking around 3pm or so (going by memory here). Winds worst during winter and spring, lowest during summer, in terms of velocity. I wrote an article on this subject, plus reduced visibility conditions which peak just after sunrise for fog and haze (lowest temperatures occur just after sunrise, based on five year statistics). Not only are summer winds lowest speed, but hot humid air is less dense than dry cold winter air. If everything constant, 10 mph crosswind during summer has less sideways push on projectile than winter wind of same speed. This is why airplanes take longer to get off runways during summer heat, less dense air means less lift under wings at same speed. In Albany NY, the hottest temperatures are usually associated with the highest velocity summer winds (from west), which also holds for Newburgh, NY. But highest velocity winds of year from west and northwest during winter and spring.

The 2 second rule for "extreme range" sounds as difficult to prove as the impact of superior German optics, and may have even less validity. We have pictures of Stalin tanks penetrated at 2400m by Nashorn, which does what to the 2 second rule? Many reports credit Tigers with accurate fire at over 2000m, and 2 seconds yields 1560m for 88L56. With careful bracketing and a stable platform 2000m is no big deal for Panther and Tiger. If an "average" Panther crew starts with a 25% range estimation error and correctly uses bracketing against a 2400m stationary target (2m high x 2m wide), the following is the theoretical hit % progression: 1st shot: 3% 2nd shot: 13% 3rd shot: 18% 4th shot: 23% 5th shot: 23% 6th shot: 27% 7th shot: 30% Hitting something at 2400m with a 780 m/s muzzle velocity is far from silly given clear sights, careful attention to bracketing and low scatter at constant aim. 2 seconds at 935 m/s is 1870m for Panther, which is far below the range at which the tank could hit. Reports given to Eisenhower seem to verify that Tigers and Panthers and Tiger II's could hit beyond 2000m. About T34 sights, German reports in Jentz' Panzertruppen series indicate that T34 could hit panzers and knock them out with amazing accuracy beyond 1200 to 1400m. Stories abound of poor T34 gun alignment and stability (it could be shaken side to side by pushing it), and rubbish sights. Of T34 crews so bad they had to close to 500m to hit anything. Russian tank capability and accuracy ranges from very poor to unheard of, like the KV-II that knocked out tanks and ATG and 88's with single shots using a low velocity gun. Regarding American sights, if American sights were not inferior to German under low light conditions (like a continuous overcast that lasts for weeks and months), why did U.S. tankers constantly talk about the superior German sights and their inability to see things well enough? Maybe the inferiority of U.S. sights only showed up when ambient light levels were below a certain threshold.

On most tanks, firing at the front armor with a lateral angle increases the resistance, but that funny glacis armor on IS-III changes things. Shots aimed directly along hull facing will impact the glacis at 58° from normal. If a shot is angled at 15° to one side of hull facing, the glacis impact angles will be: 53.6° on near side armor closest to firer 64.1° on far side armor furthest from firer Is this an academic point given the thicknesses? 120mm glacis armor on IS-III attacked by 128mm APCBC and 88L71 APCBC has following resistance at abovenoted angles: 128mm APCBC 336mm at 0° lateral angle (58° impact) 283mm at 15° lat angle (15° near side hit) 454mm at 15° lat angle (15° far side hit) 88mm APCBC 368mm at 0° lateral angle 310mm at 15° lat angle and near side hit 508mm at 15° lat angle and far side hit The turret appears to be set up so that hits on front aspect have very high resistance even though armor thins out as it gets higher on turret (220mm where it meets hull to 110mm at top). Angle increases as thickness decreases, from 45° at bottom to 90° at top. The thickness vs angle profile for the turret front is open to debate, some sources list at 160mm with round shape, starting angle may be 45° with increases towards top. The 200mm mantlet seems to be the only vulnerable area to 128mm hits. The front lower hull (120mm at 53° from vertical), would resist at 277mm and might be penetrated at point blank range. The side hull armor presents more resistance than the Panther glacis: 85mm at 55° on Panther front 90mm at 60° on IS-III hull side, plus 30mm at 30° spaced from hull covering hull side IS-III hull side resists Tiger II hits with 279mm resistance if hit has no lateral angle, which will defeat almost all hits when cast armor deficient is considered. IS-III versus Tiger II would be one very interesting match-up. P.S. American analysis of IS-2m found in Berlin ruins showed that lower turret areas, where they fit into turret ring, were very brittle and might crack on defeated hits higher up on turret, due to impact stresses carried to turret race. Which would effectively disable tank gun. One might suspect that there would be some "Achilles Heel" areas on IS-III that may not be obvious from armor thickness calculations. [ 06-18-2001: Message edited by: rexford ]

Folks think that 6 pounder AP was just fine against Tiger, it wasn't. If shots had too much penetration they shattered, which is evident from test data in Jentz. 6 pounder penetrated Tiger at range where shatter failure odds were minimal. 17 pounder AP knocking out Tigers at 1500m does not rule out shatter failures at other ranges, it indicates that at that range the shatter phenomena didn't occur cause penetration was outside shatter range. At close range 17 pounder could shatter fail against mantlet armor on Tiger I. Brits had wonderful 17 pounder ATG, Germans had 88L71 which was worlds better. Brits had backwards facing Archer, Germans had armorless Nashorn (with mild steel plates, if one can call them that). A couple of well camouflaged Marders and Firefly is toast.

If an equal number of Fireflies and Tigers faced off, who wins most often? If Tigers support German infantry attack on Allied stronghold, or Fireflies support Allied attack, who wins most often? Firefly with all-cast hull is one of the most vulnerable targets of war, only good thing about cast hull is that shots that land towards outside edges will bounce due to large impact angle. There is a chance that 17 pounder hits on Tiger mantlet will shatter fail when they overpenetrate at most combat ranges. Hulldown, a Tiger has it all over a Firefly. In frontal confrontations: It takes a Firefly to deal with a Tiger, it takes a PzKpfw IVH or StuG IIIG or Marder to deal with a Firefly (comparison limited to 75mm thru 88mm gun vehicles). Don't mention Firefly in same breath as Tiger. Blasphemy!

Without APDS 17 pounder bounces off Panther glacis at all ranges, even the badly flawed armor. However, 17 pounder APCBC at Isigny did crack the Panther glacis at 200 yards or less, making follow-up hits near the crack penetrations if close enough. With 17 pounder APDS, maybe half the hits really hit and have a chance to penetrate. British reports indicate that after firing APDS 17 pounder accuracy might suffer big time, something that did not occur after 76mm guns fired HVAP. 17 pounder penetration advantage over 88L56 on Tiger, firing APCBC, is not that great, maybe 14mm at point blank. If 17 pounder barely penetrates a target damage might be small, 88 has HE filler that detonates which makes it more dangerous. Tiger fired HE at 810 m/s which is relatively high velocity, good at hitting vertical targets. What was 17 pounder HE fired at?

A few notes on estimating and using trajectory equations. Traditional physics equation works well compared to more cumbersome approaches: trajectory height =(tangent gun elevation) x range - 0.5 x 9.81 x (flight time)squared gun elevation = (4.91 x time to aimed range/aimed range) If 88L56 is aiming at a 700m target, the flight time to 700m is 0.936 seconds, so tangent of gun elevation is 0.00615. trajectory equation for 700m aim is: 0.00615 x range - 4.91 (flight time)squared If target is at 900m when aim is at 700m, flight time is 1.22 seconds to 700m and trajectory height at 900m is .00615 x 900 - 4.91 x (1.22) squared, or 1.77m below target aim point (usually the observed center of mass). At 500m aim, the trajectory equation for 88L56 is 0.00428 x range - 4.91 (time)squared If target is at 650m with 500m aim, trajectory at 650m is 0.9m below aim point, which should be a hit against 2m high target height. One can aim at 500m with 650m target range and still hit at least 50% of shots with Tiger 88, since round to round scatter will bring half the shots up onto target. The above equation tends to overestimate trajectory heights by a slight amount. A full explanation of the above approach is available on the Saumur web site http://musee-des-blindes.intranets.com/login.asp?link=

The interesting thing about Russian AP is that 85mm, 100mm, 122mm and 152mm had it, 45mm and 76.2mm did not, based on drawings and data on The Russian Battlefield. 85mm AP and APBC seem to have both been common, same for 122mm. Maybe they decided to continue the AP lines after APBC was started due to a variety of factors, including more expensive APBC. Have you ever seen any Russian tactical advice regarding "use AP at short range, APBC at longer ranges" due to benefits from ballistic cap. If this was used in practice, and I made that doctrine up for discussion purposes, then 122mm AP would bounce off Panther at many ranges while APBC that could penetrate stayed in racks. It is also possible that one could not decide which ammo they would receive, if AP trucks made it thru Luftwaffe attacks you got AP, or APBC, or nothing but HE (which seems to have been used against some Panthers, welds cracked or glacis shattered when hit by 152mm HE). Do you know anything about this sort of thing?

Thanks alot Kip for info regarding IMO's.

Clarification on previous post. Russian APBC does not have armor piercing cap that increases penetration against face-hardened armor (and reduces homogeneous penetration), APBC has windshield to reduce air resistance.