rexford

John Salt posted the following on the CMBB forum regarding combat reports of American use of 57mm APDS: "Vannoy & Karamales' "Against the Panzers" (McFarland, Jefferson MC, 1996) says on page 280: "Each of the 57mm guns had as part of its ammunition supply seven to ten rounds of British discarding sabot (DS) ammunition, which had been issued before D-Day." The action that is described there is that of 2 Bn 28th Inf at the Domane Butgenbach. Unfortunately the account is not keyed to references to sources, but I would guess that the relevant source document is one or other of 26th IR (1st ID) AAR Dec 1944 and 26th IR (1st ID) Unit Journal, Dec 1944 - Feb 1945. The reference given for both is 301-INF(26)-0.3 at the Washington National Records Center, Suitland, MD." [ July 02, 2003, 08:27 PM: Message edited by: rexford ]

My own research on U.S. use of British 57mm APDS uncovered a firing test report by First U.S. Army, where penetration range trials were held on July 12-30, 1944 against captured Panther tanks. Ammunition use considers rounds available to First U.S. Army and considered normal types, which included 57mm sabot and 57mm M86 APC, and rounds available but considered special, such as 75mm HEAT M66. Penetration ranges could not be determined for 57mm sabot or APDS due to difficulty hitting the target, which was a common problem with WW II APDS.

In response to my inquiry, Claus Bonnesen posted the following on the Russian Battlefield site regarding past contributions on U.S. use of British 57mm APDS: "As for the report, it is probably long gone from Tankers Net, but here is what I've saved: Post by Rich Anderson on Tankers Net 09-13-2000, 07:53 2nd U.S. Infantry in the (German) Breakthrough, 38th Infantry: "During the course of the action a few noteworthy lessons were learned. Firstly, determined infantry armed with its organic weapons will stop German armor, principally by use of the rocket launcher (Bzooka) and by destroying the attack of the accompanying enemy infantry. Secondly, the 57mm AT gun with normal AP amunition was found to be of such little value that I regard it as a practically useless weapon. With the special "sabot" ammunition in abundance the weapon could be of great assistance in repelling enemy armor. I am, nevertheless, convinced it should be replaced by a self-propelled weapon of greater anti-tank possibilities..." F. H. Boos, Col., Inf., Commanding. Also, appended to the 38th Infantry AAR was this "Report of Towed 57mm Guns (AT) in Rocherath-Krinkelt Action: "...57mm guns knocked out two Panther....The first round (regular A.P.C.), fired at the side of the turret at about 175 yards riccochetted and had no effect. The second round was a hyper-velocity "Sabot" round and penetrated...I recommend the following changes in basic load: Type Present Recommended AP or APC 60 10 "Sabot" 6 30 HE 13 20 ...I also recommend the development of canister ammunition..we have found the present issue of HE effective...butconsidering the reports on 37mm canister, 57mm canister would be more effective than HE. /s/ J. W. Love, Captain, 38th Infantry, Comdg, AT Company." I have found more references to both 57mm HE and 57mm Sabot in wartime US unit reports. The 90th Division AAR for August 1944 has a G-4 Summary which mentions 57mm HE (Br.) and 57mm Sabot as being "continually desired" (I imagine for the Sabot!) while "limited quantaties" only were available. So, it appears that the issue HE round was in fact British. As for the sources: Captain Love's quotes are from the After Action Report of the 38th Infantry, 2nd Division, dated 5 January 1945, on the actions of December 1944 (engagements at Wahlerscheid, Krinkelt-Rocherath and Elsenborn), Colonel Boos' quotes are from the combat interviews compiled by theater historians, also in January 1945. The source is the US National Archives, specifically the Archives II facility at College Park, MD. The hold the records of the US Army Adjutant Generals Office and the complete srt of combat interviews generated by theater historians in World War II. Also, neat stuff like the entire archive of Signal Coprs still and motion pictures, microfilm of the German Wehrmacht archives and so on. Claus B" [ July 02, 2003, 05:17 PM: Message edited by: rexford ]

In combat and firing trials, U.S. 76mm HVAP could penetrate the Panther glacis on a small percentage of hits at 100 yards, and sometimes at 200 yards. Having a brittle glacis plate would help.

Jeff had previously noted that Panzer IV Universe's data on 75mm cannister might have come from a von Senger und Etterlin book, which would mean that we would still be left with one source for German cannister. It would be good if Jeff could check all of the details presented in the Panzer IV Universe entry on 75mm cannister with the info in von Senger's book. Looking at the sources Panzer IV Universe presents for German 75mm ammo, the following list is noted: F. M. von Senger und Etterlin, Die Kampfpanzer von 1916-1966 US Army, "TM-E 30-451; Handbook on German Military Forces, 1945" US Army, "TM 9-1985-3/TO 39B-1A-10; German Explosive Ordnance (Projectiles and Fuzes)" US Army, "Historical Study 20/269; Small Unit Actions During the German Campaign in Russia" F. W. von Mellenthin, "Panzer Battles" Walter Stutz, "Schiesslehre" Rudolf Lusar, "Die deutschen Waffen und Geheimwaffen des 2. Weltkrieges und Ihre Weiterentwicklung" I see at least two American TM documents on German ammo that could be possible sources for 75mm cannister details, unless someone can rule them out after close examination of the contents. Perhaps sources other than von Senger provided the very detailed data Panzer IV Universe contains (960 9mm balls). I'am currently tracking down the original magazine articles that Mark Diehl wrote on German ammunition, and my memory recalls a reference in the article to 75mm cannister coming in handy against Russian human wave attacks. But I'am gonna check the original article just to be sure. [ June 28, 2003, 09:22 PM: Message edited by: rexford ]

Jeff stated "Or are we talking about a handfull of 6-pdr SABOT rounds rushed over from 21st Army Group stores by the British for these 1st Army trials? If British, how much SABOT ammunition was provided? 57mm firing trials were conducted in December of 1944 by the 44th ID against a combat damaged Panther. (Headquarters 776th TD Battalion, Effectiveness of fire of 57mm Anti-tank Gun on Mk V Tank, Capt. Louis Wable, Dec 11, 1944). There is no mention of 57mm SABOT; there is no mention of 6-pdr SABOT within the report either. Nor was SABOT used in the trials. If the round was so common within US Army inventories ? as you are implying ? why weren?t 57mm SABOT trials conducted by the 44th ID? " I believe that the AAR posted by John Salt indicated that 57mm sabot was given to U.S. troops prior to D-Day, which is what Bob McNamara found in his research. If the First Army report indicates that 57mm sabot was an available and normal ammo, it suggests that it was not rushed over for the tests. Not every unit and gun had 57mm sabot, and the relative inaccuracy of the round may have discouraged its use in some tests.

Jeff stated: " You are suggesting that a US 57mm SABOT round was produced? If so what was the official projectile designation. Even projectiles still under development will have a designation." I suggested nothing like that, and addressed the designation issue in previous posts on this thread. 57mm sabot was of British origin, which could explain the absence of U.S. M and T numbers. During his research for a wargame, Bob McNamara also found that the British gave the Americans some 57mm HE rounds, if memory serves me correct. This is in addition to the limited run of U.S. made HE for their 57mm guns. The fact that Bob McNamara documented his research in a wargame, as opposed to a magazine (1983 research), does not detract from his findings in my view. He also discussed the issues with me and explained his finds. I sense that this discussion is starting to go round and round on your part. You might wish to read my previous posts since you appear to have forgotten issues which were previously discussed. The U.S. Army firing test report indicates that 57mm sabot was available and considered a "normal" ammunition, which does not mean it is plentiful or available to every gun. I stated this in an earlier post. If you read the U.S. Army firing test report you'll see the context for "normal" versus "special" ammo. 57mm sabot is "normal", 75mm HEAT is "special", for instance It would be expected that many or most 57mm guns would not have access to 57mm sabot, so the normal ammo load could be addressed without mentioning 57mm sabot, and would not contradict the use of the same word (normal) in the U.S. firing test report. "Normal" as opposed to "special". Read the U.S. firing test report.

Why should a muzzle brake produce any loss of m.v.? Assuming that the driving band produces proper obturation, the propellant gases do not act on the brake until the projectile clears the muzzle, as is mentioned in the Hunnicutt article referred to above. All the best, John. </font>

Interesting that no questions were raised when I repeatedly referred to U.S. firing tests with 57mm APDS against captured Panthers in France. Jeff can add this to the list of references to U.S. use of 57mm APDS. Surprised that he wasn't familiar with the report as a reference to U.S. use of 57mm APDS. Following are highlights from the report: Organization: Headquarters, First U.S. Army "Proceedings of a board of officers which convened at Headquarters, First U.S. Army, pursuant to Special Order 196, Headquarters, First U.S. Army, 19 July 1944, a copy of which is attached as Exhibit A(1)." Firing tests conducted July 12-30 1944. "Purpose: To conduct tests to determine the effectiveness of tank and anti-tank weapons in First U.S. Army, against the German Mk V Panther and Mk VI Tiger tanks." "1a. Firing was conducted on terrain permitting 1500 yards maximum range with zero angle of site. All guns and types of ammunition, suitable for anti-tank purposes, available to First U.S. Army were defeated on targets whose armour was slighly burned." "The following normal types of tank and anti-tank weapon and ammunition were tested; WEAPON ====== 57mm Gun, M1 AMMUNITION ========== APC M86 Sabot" Another vague reference? Weapons and ammo available to First U.S. Army, and normal types of ammunition. Nothing special is noted about 57mm sabot, it is not noted as experimental or for this test only. The report notes that troops had trouble hitting targets with 57mm sabot, a common enough problem with that type of ammo. I'll let you guys bounce that around for awhile. [ June 21, 2003, 08:43 PM: Message edited by: rexford ]

"The excellent work on Amedeo's part actually produced an official Soviet Army publication on Artillery Gunnery....not a wargames rule booklet." Jeff seems fixated on the connection between 57mm APDS and Advanced Squad Leader. Robert McNamara uncovered the U.S. ammo use tables with 57mm APDS evidence back in the 1980's. Those tables might still be there, I'll ask Robert McNamara where he found them. [ June 19, 2003, 08:25 PM: Message edited by: rexford ]

I have a 1942 German report on Russian 76.2mm field guns and there is no mention of case shot but tons of info on shrapnel. Shrapnel with fuze set to go off just beyond the muzzle is mentioned for close defense.

Vannoy & Karamales' "Against the Panzers" (McFarland, Jefferson MC, 1996) says on page 280: "Each of the 57mm guns had as part of its ammunition supply seven to ten rounds of British discarding sabot (DS) ammunition, which had been issued before D-Day." The action that is described there is that of 2 Bn 28th Inf at the Domane Butgenbach. Unfortunately the account is not keyed to references to sources, but I would guess that the relevant source document is one or other of 26th IR (1st ID) AAR Dec 1944 and 26th IR (1st ID) Unit Journal, Dec 1944 - Feb 1945. The reference given for both is 301-INF(26)-0.3 at the Washington National Records Center, Suitland, MD. Personally I tend to think that a one-time issue of 10 r.p.g. makes APDS in American service about as widespread as hen's teeth; and I, too, would like to see a picture of a German 7.5cm canister round. Given the extraordinary effectiveness of both these kinds of round, I would think it reasonable to have heard more about them if they had really been used at all widely. All the best, John. </font>

57mm APDS shows up in a July 1944 U.S. firing test sequence against Panthers in France as a common ammunition (not special), and it shows up in U.S. AAR reports for combat in Germany. And Robert McNamara's research showed that U.S. forces seem to have continuously had some 57mm APDS, though in relatively small quantities and maybe only certain units. Robert McNamara's research was for a wargame but so what? Jeff's statement that McNamara included 57mm APDS for a what-if game scenario strikes me as not making much sense, since it flies in the face of the McNamara research that I clearly stated supported 57mm APDS use by U.S. forces. McNamara found that U.S. ammo consumption tables showed 57mm APDS ammo use starting with the D-Day landings. If McNamara found info supporting combat use of 57mm APDS a what-if scenario is clearly not needed. Where did Jeff get the what-if scenario idea? Jeff had no trouble accepting Amedeo's fine research on Russian 76.2mm shrapnel use as cannister at close range, even though that was for a wargame (CMBB). But he readily dismisses McNamara's findings as wargame speculation. Will Jeff treat Amedeo's finding as a what-if wargame scenario? If we find ONE example of actual combat use for 57mm APDS by American forces, it destroys Jeff's argument that it never occurred. And we have. With regard to the question as to why we haven't heard more about its use, I don't know. One could ask why a report to Eisenhower on the sad performance of U.S. tanks against panzers was delayed until 1945. Things happen. As far as proving British shipments and estimating the quantities, the fact that 57mm APDS was used in combat is enough for me. I leave the other stuff for other folks. The basic question has been answered, was APDS used by U.S. 57mm guns. 6 basic rounds of APDS available to at least one U.S. unit's guns, and an AAR report that the round penetrated a Panther in combat. End of argument, U.S. 57mm APDS was used in combat. The other questions that have been raised are secondary to the issue of was it ever used. [ June 18, 2003, 09:03 PM: Message edited by: rexford ]

You're right. That's why all of Jeff's research couldn't find anything. 38th Infantry AAR has a "Report of Towed 57mm Guns (AT)" that indicates the basic ammo load for the weapons: 60 AP or APC 6 sabot 13 HE The 13 HE rounds were a "kitty" built up in Normandy. Report references use of a hypervelocity "Sabot" round, which penetrated a Panther. The Americans sure knew alot about a round they supposedly never used. The July 1944 firing tests by American forces against captured Panthers, which took place in France, indicated that 57mm APDS was a common round, as opposed to a special ammo such as 75mm HEAT.

Jeff's response starts off with some histrionics that miss the point. Robert McNamara researched U.S. documents and found references to consumption of 57mm APDS by U.S. forces in two theaters. Whether he did the research for a game is besides the point, but declaring research to be inadmissible because it was done for a game is an easy way to dismiss the conflicting material. Play fair, Jeff. I corresponded with Bob McNamara on the issue outside of using what was inside ASL, because I wanted to see what he used before I took it as reasonable. With regard to U.S. production of 57mm APDS, many many posts on various forums have indicated that it was of British origin. Claus Bonnesen in his Yahoo! Tankers post on 57mm APDS indicated that you won't find any Txx or Mxx numbers for the ammo since it was British. The need for a specific gunsight for 57mm APDS was also discussed at great length, since several poeple felt that something should show up. Not necessarily, since the British never did produce specific gunsights for 6 and 17 pdr APDS, gunners used the APCBC elevations multiplied by a factor (2/3 for 17 pdr APDS). I assume the Americans would do the same. U.S. 57mm APCBC would have similar flight ballistics to British 6 pdr APCBC (both fired at about 2700 fps with similar weight), so using the British elevation multiplier would work fairly well with U.S. 57mm APCBC gunsight markings. The U.S. did not generate specific gunsights for 90mm HVAP, gunners used a table they would attach to the wall. If one uses a multiplying factor for APDS elevations there is no need for ballistic tables. All of this has been discussed on many forums, and perhaps you should get up to speed. [ June 18, 2003, 06:19 AM: Message edited by: rexford ]

Jeff stated that "Ideal burst height for 75mm Shrapnel was about 30-feet. This is evident at least from both US Army and French Army gunnery manuals of the period. However gun crews were typically trained to set their time fuse for a 60-ft airburst. Another example of the contrast between theory and practice. Deliberately setting for a 60-ft airburst was again a function of fuse slop\inaccuracy. The logic apparently being that a high airburst was still more effective against troops in the open than a ground burst." The German pages that are posted on this site indicate that Russian 76.2mm shrapnel was detonated a few meters above the ground. Look at those pages.

I would strongly disagree with Jeff's assessment of 57mm APDS use by U.S. forces during WW II. Since Jeff is a member of the Yahoo Tankers site, he must have missed the post by Claus Bonnesen which discussed AAR cases where 57mm APDS was fired by U.S. forces during combat. 38th Infantry AAR in Rocherath-Krinkelt action had 57mm sabot penetrate Panther turret side after AP bounced. 90th Division AAR for August 1944, G-4 summary, talks about how 57mm sabot is continually desired but only available in limited quantities. Claus had some posts from the Tankers Net site that he shared with us on the Yahoo! Tankers site, which is where the preceding info came from. Jeff may be familiar with the July 1944 firing test report where U.S. forces determined penetration ranges against captured Panthers. Burned vehicles were used during the initial tests and then the better tanks were brought out to validate penetration ranges. 57mm APDS was fired by the Americans and had trouble hitting targets. I have also noted several times in the past that Robert McNamara studied U.S. combat ammo use tables and was able to locate APDS use by 57mm American guns, a fact that he used during the design of Advanced Squad Leader.

Actual measurement of the Panther nose armor resulted in 66mm at 55 degrees from vertical, which resists 76mm APCBC like 159mm vertical and cannot be defeated at any range. So against a real Panther on level ground, 76mm APCBC would fail on almost every hit against the front hull at 10 meters range. Ordnance Officer indicated 1600 yard or 1463m effective range. Too bad no one ever thought of an actual test fire before D-Day against some captured Panthers in Russia or Italy. [ June 15, 2003, 06:33 PM: Message edited by: rexford ]

The Americans did penetration calculations prior to D-Day that showed that the Panther was vulnerable to 76mm APCBC beyond 1000 yards. Many penetration ranges that one comes across in official publications are garbage, prepared by someone in an office far from the front using whatever data is officially sanctioned. Much of the accepted data was not validated against firing tests or combat results. If one applies the APCBC slope effects for the 80mm at 55 degree Panther glacis they obtain about 176mm vertical resistance. If they compare that resistance to the 76mm HVAP penetration, the effective range looks like 1100 yards or 1000 meters. Only problem is, HVAP has much higher slope multipliers so 80mm at 55 degrees resists like 276mm vertical. There are MANY wargames and books that miss the fact that 76mm APCBC and HVAP are faced with different effective resistances when they hit 80mm plates at 55 degrees from vertical, and this occurred more than 40 years after the war ended. The John Salt site presents some of the pre D-Day penetration range estimates for U.S. ammo against Panther, with a few notes post D-Day regarding how theory and actuality differed by quire a bit. I'll look for the specific reference on the John Salt site statements.

"Well, 500 yards was a "typical combat range." Yeah, but 76mm HVAP would only penetrate the lower hull front on a Panther A at that range on half the hits without any angle between firer and hull facing. Under actual conditions there would be some angle involved on many hits. And as the firing tests at Isigny showed, major areas of the lower hull front armor on Panthers would be blocked from sight due to ground folds and small hills, so the vulnerable area would be much reduced. 76mm HVAP was great against PzKpfw IV and StuG, and Tigers, and the side armor on Panthers. But face-to-face against a Panther at 500m, 76mm HVAP bounces off the glacis every time, while Panther hits on Shermans might bounce when they go through the first tank and strike the front of another Sherman following on the same road.

I have a German translation of a Russian manual for 76.2mm field guns, and the muzzle velocity of the field guns with a muzzle brake is the same as the T34 tank gun with BR-350A ammo. If one wants 662 m/s for BR-350A, and 655 m/s for BR-350B from both field and tank guns, you put a little more charge in the field gun ammo when there is a muzzle brake. Simple. The 680 m/s for T34 APBC is a mistake I am responsible for, Russian Battlefield quotes that velocity for BR-350B and I told the CMBB people it was correct. 680 m/s is for 76.2mm HE, 662 m/s is for BR-350A and 655 m/s is for BR-350B, based on "current thinking" (a select group of folks, myself included, who guess at things with varying accuracy and occasional fits of wild inaccuracy).

"-- HVAP ammo did allow the 76mm gun to kill Panthers, at least, from the front at typical combat ranges. HVAP became available shortly after COBRA. The problem was not in the thinking--it was getting the ammo to the crews." No it didn't. 76mm HVAP was effective against the Panther glacis at 100 to 200 yards tops, although it would penetrate the mantlet and nose armor at much further ranges. But 76mm HVAP was highly accurate, which meant it usually landed close to the aim point, and the usual aim point was the Panther glacis armor. 76mm HVAP would routinely penetrate the Panther A nose armor (65mm at 55 degrees from vertical) at less than 500m. Panther G's with 50mm armor at 55 degrees from vertical would be vulnerable at a greater distance. When 76mm APCBC failed, the Americans thought 76mm HVAP would solve things. It didn't. [ June 13, 2003, 05:46 PM: Message edited by: rexford ]

Prior to D-Day, Allied calculations indicated that the U.S. 76mm gun would be able to handle Panthers and Tigers beyond 1000 yards range. I've seen estimates for 76mm APCBC against the Panther front hull nose armor that expected penetrations at 1200 yards. Actual penetration ranges were much lower than the Allied estimates.

The ZIS-3 Model 1942 76.2mm field gun had a barrel length of L41.5, based on a German report I have, and was no different from the T34 76.2mm gun in terms of muzzle velocity. Could you share the reference regarding ZIS-3 76.2mm firing APBC at a lower muzzle velocity. The German report I have has the L41.5 and L40 76.2mm field guns firing BR-350A APBC at 662 m/s. Maybe the L37 length for the Model 1942 gun is based on a different definition than the T34 L41.5 length.

"The A ring subtends 0.1 radian, and contains 50% of the balls. The B ring subtends 0.2 radian, and contains a further 32% of the balls. The C ring subtends 0.3 radian, and contains a further 14% of the balls. The D ring subtends 0.4 radian, and contains the remaining 4% of the balls." For 76.2mm shrapnel, the scatter cone widens to 20m in an 80mm distance from shell detonation, which subtends 0.25 radians for the entire area. Using 0.4 radians for 76.2mm shrapnel seems to result in a decreased hit probability compared to 0.25 radians, since the ball density is much lower with 0.4 radians. For innermost ring at 100m with 300 balls: 0.4 radians for all rings, 0.1 for inner ring ============================================== hit probability = 1 - (1 - 0.00636)^300 = 0.85 0.25 radians for all rings, 0.0625 for inner ring================================================= hit probability = 1 - (1 - 0.01629)^300 = 0.99 0.1 radians for inner ring at 100m from detonation results in an area of 78.7 square meters. 0.0625 radians for inner ring at 100m from detonation results in an area of 30.7 square meters. 1 radian equals 57.296 degrees.