rexford

German 37mm AP is a large HE burster armor piercing round (1.9% of shell is burster, as opposed to 0.2% for 75mm L43, L46, L48 and L70.

At 800m, Hetzer 60mm/60 degrees presents 144mm vertical equivalent to 85mm APBC prior to armor quality factor. At 800m, T34/85 high hardness glacis (60mm/60 degrees) presents 122mm vertical to 75mm APCBC prior to high hardness multiplier (0.76) and armor quality. So Hetzer glacis should not be penetrated by T34/85 APBC at 800m, and T34/85 glacis should be easy pickens. Hetzer is smaller target. Hetzer lower nose on front is very vulnerable, 60mm at 40 degrees resists 85mm APBC like about 80mm vertical x quality. Hetzer should kick T34/85 butt at 800m and 1000m in majority of cases. In some games, T34/85 will win due to random effects.

German 37mm AP round has an HE burster and is fired at lower velocity than U.S. 37mm and British 40mm AP. 37mm AP L45 is also lighter in weight than 37mm APCBC and 40mm AP. Penetration data suggests that German 37mm AP had some pretty sad metal quality.

The 30 degree penetration table in Jentz Panzertruppen and Encycl. of German Tanks has 20mm AP defeating 20mm at 100m. British collection of German data has 0 degree estimate of about 45mm at 100m, which does not match up with 20mm at 30 degrees. So table data at 30 degrees does seem deflated. Amedeo Matteucci brought up Russian account where 20mm penetrates 45mm vertical on T34, and 37mm penetrates 45mm/40 degrees on T34, at close range. Table data for both guns would not support either result. German armor acceptance table from BIOS report shows that 42mm plate was expected to resist 37mm AP hits at 100m and 30 degrees without allowing a through-the-plate crack. I wonder if that is the origin of a 42mm penetration figure at 100m and 30 degrees. Armor acceptance tables are NOT penetration performance, they are based on the "sicher" criteria where armor had to avoid see-through cracks in order to be accepted. If 42mm of German armor plate does not crack on the inside at 100m and 30 degrees, clean penetration performance of 37mm AP is going to be quite a bit lower. We have never found any German penetration figures against face-hardened armor, they tested armor that was going to be face-hardened while it was still homogeneous when it came to ammo firing trials. I have data from 1942 German trials against face-hardened and T34 armor with 37mm AP (40mm to 53mm plate), 37mm gun could not penetrate 40mm of face-hardened plate at 100m and 0°. 37mm AP has an HE burster that is 1.9% of total weight, which is high. 75mm APCBC has 0.2%. There is evidence which suggests that early war German ammo was inferior to 1942 stuff. There is a possibility that 37mm AP was improved after 1941 along with 20mm AP when they just didn't cut it anymore. Germans attempted to improve 50mm performance at 45 degrees during late 1942 through 1943 by changing composition and other factors. Tests did not show a change. Fact remains that German 37mm AP at 100m was not expected to cause a crack clear through a good quality 42mm thick German plate at 30 degrees, so is it likely that it would completely penetrate more than 40mm at that range. Jentz figure of 35mm complete penetration at 100m and 30 degrees is consistent with the German armor acceptance curves.

German armor acceptance curves show that a 55mm plate at vertical was expected to stop 37mm AP hits at 100m without any through-the-plate cracking. That being the case, do you trust 0m/0° penetration of 68mm or 50mm for 37mm AP?

Here is the May 1942 German data for 37mm ATG against T34 armor using AP rounds at 100m: 40.6mm plate: shots at 40° and above would not cause a crack on inside of plate (sicher criteria, similar to U.S. Army Ballistic Limit) 45.8mm plate: shots at 21°and above do not cause through the plate cracks 47.7mm plate: shots at 15° and above cause no through cracking 51.9mm plate: hits above 10.5° cause no cracks through plate Combat stories indicating that 37mm ATG AP penetrated 45mm at 40° T34 side at 300m range appear highly questionable when they are compared to above firing trial results.

When combat reports are analyzed for T34 kills, Model 42 had 65mm turret front and side, which obviously changes results compared to earlier models.

During May 1942, the Germans duplicated T34 armor in 40mm through 53mm plates and fired 37mm L45 and 50mm L60 rounds at the armor (100m range). Following is summary of 50mm L60 results: 40.5mm at 40°, 3 penetrations, 2 failures Since all the hits should have succeeded, something odd occurred. May be shatter gap, may be cracked rounds. Sure penetrations turn into 40% failure rate. 52mm at 55°, 4 failures 46mm at 60°, 1 penetration, 3 failures German combat experience showed that 50mm ATG could penetrate T34 glacis at 100m if everything was in favor of round 52mm at 61°, 4 failures 47mm at 64.5°, 3 failures 43mm at 65°, 1 success, 2 failures This supports occasional penetration of T34 glacis if everything is just right Based on analysis of the above data, T34 high hardness armor appears to be less resistant than good quality medium hardness plate (quality is less than 1.00 against 50mm hits). Above summary thicknesses are averages, actual thicknesses at each angle varied.

The armor figures in CMBB for the IS tanks is from a British Intelligence report published after the war, which is based in part on data given to British operatives in Russia during the war. Paul Lakowski loaned me the report, and I submitted the data to the CMBB design team. I checked the British figures against American analysis of IS tanks found in the ruins after the Berlin fighting, and German analysis of captured IS vehicles. IS-1 and early IS-2 with 30° driver plate 105mm glacis at 30° 95mm nose at 30° 100mm turret front and mantlet rounded IS-2 late model with 60° glacis 110mm glacis at 60° 127mm nose at 30° 100mm turret front and mantlet rounded A German photo shows 110mm for IS-2 mantlet. The German photo's show design thicknesses, since armor would rarely be exactly 95mm or 105mm thick when measured in the field.

Comments raised on the CMBB forum resulted in re-examination of penetration data for early war 37mm, 50mm and 75mm German armor piercing ammo, which appear to match up better against expected results against T34 and KV tanks: 37mm L45 AP 48mm at 100m 45mm at 250m 39mm at 500m 34mm at 750m 30mm at 1000m Data developed by converting 30° figures in Jentz Panzertruppen to 0° using slope multipliers and armor hardness effects. Projectile metal in 37mm AP appears to be very inferior to 75L43 APCBC. Turret front successes against T34 will be severely reduced. 50mm L42 APC 75mm at 0m 71mm at 100m 66mm at 250m 58mm at 500m 45mm at 1000m Data lowered to be more consistent with American and British estimates. KV-1 75mm armor vulnerability reduced significantly. 50mm L60 APC 99mm at 0m 94mm at 100m 88mm at 250m 77mm at 500m 59mm at 1000m Data lowered to be more consistent with American and British estimates and German tests against KV-1 75mm/30° during spring 1942 (round succeeded at 100m and failed at 200m). 75mm L24 APCBC 50mm at 100m 49mm at 250m 47mm at 500m 46mm at 750m 44mm at 1000m Following changes follow from analysis of data in Jentz Dreaded Threat and American/British data on Flak ammo: 88mm L56 Flak (up to spring 1942) 123mm at 100m 121mm at 250m 116mm at 500m 112mm at 750m 108mm at 1000m Early war large HE burster capacity ammo 88mm L56 Flak (spring 1942 and beyond) 149mm at 100m 145mm at 250m 139mm at 500m 133mm at 750m 127mm at 1000m Later war large capacity HE burster ammo My thanks to Amedeo Matteucci and the others who brought many surprising combat results to my attention.

The following penetration data for 50L42 and 50L60 APC are reduced to consider HE burster size and to be more consistent with British and American figures: 50mmL42 APC 75mm at 0m, 71mm at 100m, 66mm at 250m, 58mm at 500m, 45mm at 1000m, 35mm at 1500m 50mmL60 APC 99mm at 0m, 94mm at 100m, 88mm at 250m, 77mm at 500m, 59mm at 1000m, 46mm at 1500m The above data results in a very low penetration percentage for 50mm L42 APC against 75mm KV-1 armor at all ranges except point blank. The 50mmL60 APC penetrated the KV-1 75mm/30° at 100m and failed at 200m in spring 1942 tests by Germans. The 75mm/30° armor resists 50mm APC like 95mm vertical, the 50mmL60 APC penetration is 94mm at 100m and 89mm at 200m using the above figures. It is suggested that CMBB use the revised figures I've presented for 37mmL45 AP, 50mm L42 and L60 APC and 75mmL24 APCBC, which would improve combat results against T34 and KV-1/KV-2. Data for 37mm L45 AP suggests very inferior projectile metal quality compared to 75L43 APCBC, and will not allow penetrations of T34 except at very close range (45mm vertical or near-vertical plates). 50mm L42 AP and APC will penetrate T34 vertical or near vertical 45mm plates out to fairly good ranges. [ October 21, 2002, 06:20 PM: Message edited by: rexford ]

Following is from a British report on the analysis of German data after WW II, which deals with long range fire by 88L71: A report from Wa A (Administration, East) Southern Russia in October 1943 said of the 8.8cm gun 41.43 that is was difficult to camouflage and to move but was outstandingly accurate. The best fighting range was said to be 2500-3500 metres. A report on the tractor drawn equipment from the Heavy Anti-Tank Battalion B said "The manoeuvravility proved better than expected. Accuracy was so good that, in some cases, A.F.V.'s were knocked out at ranges up to 5km."

30° German penetration data in Jentz Panzertruppen 1943-1945 supports lower penetration for German 37mm and 50mm AP: 37mm L45 Pzgr uncapped AP @ 30 degrees 35mm at 100m, 29mm at 500m, 22mm at 1000m 50mm L42 Pzgr uncapped AP @ 30 degrees 53mm at 100m, 43mm at 500m, 32mm at 1000m Above figures convert to following at 0° after considering armor hardness: 37mm L45 uncapped AP 48mm at 100m, 39mm at 500m, 30mm at 1000m No turret front penetrations of T34 at 500m. 50mm L42 uncapped AP 73mm at 100m, 55mm at 500m, 39mm at 1000m Penetration greater than 45mm at 500m. Jentz has following 30° data for 75L24 APCBC: 41mm at 100m, 38mm at 500m, 35mm at 1000m Which converts to 75L24 APCBC 0° penetration of: 50mm at 100m, 47mm at 500m, 44mm at 1000m At Rowno, Michael Wittmann in a StuG IIIA with the 75L24 knocked out several T34 on the first shot at each, with quite a few knocked out on frontal shots. Scissors scope and ambush tactic helped StuG IIIA suddenly break out of cover and surprise T34 before it could react, but 75L24 could kill T34 frontally. Would 50mm L42 AP fail against T34 turret front at all ranges? German tests with 50mm L42 AP against normal hardness plate show 500m penetration of 43mm at 30 degrees. Would round fail on impact against 45mm of Russian armor at 0 degree angle at 500m? I have read where Germans starting putting armor piercing caps on their ammo to reduce shatter tendencies. Maybe early war 50mm AP rounds were breaking up against very hard Russian armor. Or maybe German commanders were blaming high losses to Russian formations on T34 armor, when problem was poor tactics. Some German commanders state that 75L43 gun was great against T34 during spring 1942, knocking them out at all angles to 1200m, with a maximum range of 1600m. Some commanders from same period complain that 75L43 is inadequate beyond 1000m. Different angles, bad ammo or trying to move the blame. There has been discussion on the Tankers site that some T34 were built with medium hardness armor, an article was reviewed where the U.S. not only built factories in Russia during the 1930's that were for tractors but were converted to armor, but sent Russia armor plate prior to WW II which may have been medium hardness. We know that T34 were built during 1942 with high hardness armor, who knows what happened during 1940 and 1941. German 50mm AP rounds were probably soft enough to break up due to shatter on some hits. 50mm L42 AP should penetrate 45mm turret front on T34, why are the turret front kills given so little publicity in reports and anecdotes?

As an added confusing factor, when the Germans modelled T34 armor for their firing tests, they used 42mm to 53mm thick plates. An SU 100 nose armor, supposedly 45mm thick, was measured at 60mm. Russian armor thicknesses may have been variable.

Regarding long range hits, German reports on 88L71 ATG use indicate routine kills at 2500m to 3000m, and kills at 5000m. Gun was noted as being very accurate unless it was moved.

Grisha asked: "Would something like the Panzerbeschusstafel be compiled from fragmentary evidence? And, if so little good data exists, then why adopt a position that flies contrary to existing anecdotal, if not empirical, evidence?" The Panzerbeschuschusstafel are usually not very good, based on our experience comparing them to combat and firing test results. They do not consider high hardness T34 armor, they use all sorts of calculated penetration data that cannot be related to firing tests, and many of the results are amusing. The 37mm Panzerb. shows very little chance of cleanly penetrating the turret front and mantlet at any range, if I remember correctly. Going through our notes, the following are our revised penetration figures for German 37mm AP: 100m,48mm 250m,45mm 500m,39mm 750m,34mm 1000m,30mm The above figures are more in line with the "door knocker" reputation of 37mm AP when it is used against T34. Someone questioned our figures for 37mm AP early this year and the abovenoted revisions were prepared. I don't remember where they came from (how they were derived), but will look. According to above figures, German 37mm AP penetrates "45mm at vertical" side hull on T34 at about 250m or a little further if armor resistance is lowered due to high hardness. Ability of 37mm AP to penetrate T34 turret front should be very low at most combat ranges. German 37mm AP, using above figures, will not penetrate 45mm at 30 or 40 degrees at any range (T34 turret side and side superstructure), which seems realistic. Our original figures assumed 37mm AP has same penetration characteristics as German 75mm APCBC after modification for caps, but 37mm AP has very large HE burster (1.9% of total weight in 37mm is burster vs. 0.2% in 75mm),and may have had lower quality metal. The war reports in Jentz are fragments with alot of missing information, particularly the number of encounters, the number of shots that landed and the impact angle (vertical slope and lateral side angle of shot). Jentz' books present ranges that are missing most of the really vital info, due entirely to the character of the German reports, so the information is really next to useless when it comes to 50mm L42. It can easily be misleading. If one assumes that Russian T34 armor does not suffer a deficiency against 50mm AP and APC rounds, then the combat results are more in line with many of the OPINIONS being discussed. Or one can assume the 50mm L42 was using the lower quality and less effective uncapped AP rounds, which is why the hits failed. I would agree that the 50mm L42 vs T34 situation should be revisited with an eye towards a possible revision, and the 37mm AP "door knocker" may be too good. German tests with 50mm L60 during spring of 1942 showed that it could defeat KV-1 75mm/30° front plate at 100m, but failed at 200m. As noted in my previous post, there is evidence which suggests that German ammo for 50mm, 75mm and 88mm guns was inferior to rounds which appeared spring 1942, which could account for some of the problems against T34.

We played many games where three entrenched 37mm PaK faced off with three T34 M40 at 300m to 400m. In almost all games, the first minute resulted in several turret hits, and at least one turret penetration and one partial turret penetration. It appears that the T34 survived partial 37mm penetrations due to small projectile size. The high probability of a turret front hit is probably due, in part, to the extremely high rate of fire of 37mm ATG. German 37mm ATG crews were taught to aim at the turret ring, which would result in a higher rate of turret hits than shots aimed at the center of target mass.

Jeff stated that "The heart of this lies in inflated German penetration figures, and a shakey theory regarding Soviet high hardness armor". Please provide your case for the above in more than just general terms. Give us something to chew on! German tests with 37mm and 50mm projectiles at 100m range against T34 like armor (same composition and same very high hardness around 460 Brinell) showed that the armor plate did not resist as well as medium hardness armor (about 300 Brinell). The theories used in CMBB are based on actual firing tests against high hardness armor. The problem with those stories regarding 50mm L42 inadequacy against T34 side armor, which are presented in Jentz' Panzertruppen, is that they may be based on one or two engagements and do not give the impact angles. Maybe the shots were taken at 45 degrees side angle to the T34 armor. The 50mm L42 APC round penetrates about 66mm at 500m, the 50mm L42 AP about 55mm. 45mm medium hardness armor at 40 degree vertical slope (T34 side superstructure) resists 50mm APC like an 81mm vertical plate. If the 45mm at 40 degree plate is high hardness, the resistance will drop to 68mm of good medium hardness vertical plate if the figures in our book are used, which would allow 50mm L42 AP penetrations at 200m. 50mm L42 APC would penetrate at around 450m. Some research we did on German 1941 ammo suggested that 50mm and 88mm ammo used that year was inferior to the stuff fielded after spring 1942. This may or may not be in the present CMBB models. If 1941 PzKpfw III with the L42 gun fire uncapped AP rounds, then the combat results will come close to the fragmentary anecdotes that Jentz and others present. Our theory on T34 armor deficiencies against 50mm rounds is not as "tight" as the predicted results against 75mm and larger rounds, due to limited base data for the smaller rounds. By the way, our predictions for 75mm L43 APCBC against T34 armor match up very well with Jentz' anecdotal reports published by German forces during 1942. I note that Jeff did not mention the good predictions for 75mm L43 APCBC, which have been mentioned many times on various forums and are discussed in our book (which Jeff has). It is possible that the 50mm hits on T34 armor result in a 0.91 deficiency, a situation where 50mm L42 AP rounds would bounce against 45mm/40° at almost all ranges and 50mm APC from L42 would need very close ranges. There is room for question, but there is also a shortage of real good data regarding the effective range of 50mm L42 projectiles against T34 side armor at known side angles (lateral angle from firer to armor facing).

A few notes on M4A2 vs T34/85: 1. Gun Penetration 76mm APCBC outpenetrates 85mm APCBC during Russian tests against Tiger II, as noted on Russian Battlefield site. Difference in ranges is significant. U.S. ammunition is harder than Russian, and APCBC holds penetration better with range than blunt nose APBC. 2. Armor Resistance When 75mm German APCBC hits T34/85 front hull, 45mm at 60 degrees from vertical, high hardness brittle plate acts like 93mm of good quality vertical plate. 2.5" glacis at 47 degrees on M4A2 resists like about 120mm of good vertical plate. M4A2 wins hands down against a 75mm Pak 40. U.S. plate quality improves starting 10/43 when quality control and heat treatment gets ALOT better, Russian armor on T34/95 stays about the same throughout war. BUT, M4A2 has rubbish nose armor and a nice. big and flat 89mm mantlet, while T34/85 has all that curved mantlet and turret front armor. 3. Sights German sights much superior to American and Russian cause they had better light gathering properties.b Stories from Russian front have Tigers shooting up T34 formations through fog, and Russians cannot see where shots are coming from. Report to Eisenhower on German-vs-U.S. equipment says German sights great in all light conditions, U.S. sights only good in bright light. I believe M4A3E8 has sight which was great improvement on earlier stuff. M4A2 with 75mm and 76mm probably not as good a sight as Germans, and maybe comparable to Russian. 4. Many Shermans rot on soft ground, Tigers, Panthers and even Tiger II's race over mud that bogs or slows down Shermans. T34/85 has fairly good tracks. 5. Typical Combat Ranges Alot of German reports list combat at 3000m to 5000m for guns like 88L71 and 75L70. M4A2 76mm probably better than 85mm at these ranges (not too good). 6. Blast Problems Didn't early 76mm Shermans without muzzle brakes have big difficulties with smoke and dust obscuring the view?

"It is a rule of thumb that armour is penetrable by rounds equal in diameter to its thickness" John Keegan, Author of "The Second World War". Rules of thumb are full of holes when it comes to armor penetration. Velocity is a big factor. Nose hardness is also big. Russian 152mm will not penetrate 152mm of armor, velocity is too low. In many cases, projectiles at 500m will penetrate a thickness greater than the ammo diameter.

Mobius on the Yahoo!Tankers site has posted some really good photo's of a captured IS-2 with armor thicknesses stencilled on. Sites are: http://www.panzer-war.com/images/js2.jpg http://www.panzer-war.com/images/is2_fronttop.jpg http://www.panzer-war.com/images/is2_reartop.jpg Turret front is 100mm, mantlet varies from 110mm to 70mm, 105mm at 30 degrees driver plate and 95mm at 30 degrees lower hull front.

One other interesting aspect of that story is that it suggests that Russian HE fragmentation rounds would be much more effective than U.S., German or British. British HE was inferior to U.S. because of poorer metal quality? Can anyone comment on that. I don't mean mortars, HE rounds fired by tanks and guns. Thanks. Lorrin

Thanks. Every picture is terrific. The Kursk scene is hectic looking, something that doesn't really come across that well in books. A very profitable trip, for sure! Lorrin

Sherman penetration against homogenous armor plate goes like this, according to U.S. test results: 75mm APCBC (basically the only armor piercing round fired by Shermans during 44-45 period) 88mm at 100m 85mm at 250m 81mm at 500m 77mm at 750m 75mm AP (this solid uncapped shot is very rare) 109mm at 100m 102mm at 250m 92mm at 500m 84mm at 750m Average is: 99mm at 100m 93mm at 250m 87mm at 500m 81mm at 750m CMBO is about 10% high for Sherman APCBC against homogeneous armor carried by Tiger, Tiger II and Panther, which shows up on battlefield in terms of wide angle penetrations that may be a tad optimistic. Face-hardened armor is another matter (CMBO does not seem to recognize the differences between face-hardened armor, homogeneous plate and castings): 75mm APCBC vs Face-Hardened Plate 102mm at 100m 99mm at 250m 95mm at 500m 82mm at 1250m 75mm AP vs Face-Hardened Plate 91mm at 100m 85mm at 250m 75mm at 500m Against PzKpfw IVH and StuG IIIG, which have face-hardened frontal armor, CMBO underestimates APCBC performance. It is also worth noting that uncapped 75mm AP had a reputation for shatter, and the Americans converted thousands of 75mm M72 AP to M61 APCBC by inserting an HE burster cavity. 75mm AP should be very rare in CMBO.