Mr. Tittles

The funny thing is that all the US would only have had to ship over the M36 turrets and they could have field modified Shermans to carry them. Its surprising that the US did not get the Soviets to field test weapons against the Germans and feed back info. The Panther and Tiger were both running around the east for over a year by the time the allies invaded France. Plenty of Panthers must have been falling into the Soviets hands and shipping one to England would not have been out of the question. [ October 07, 2004, 07:06 AM: Message edited by: Mr. Tittles ]

The M4A3E8 sherman with APCR is more than a match to a T34/85. If the Russians pushed it, they would have starved to death in post WWII. Strategic bombing would sever all supplies and the flow of food from the west would stop anyway of course.

Not really. 90mm AA guns were sitting ducks. Any mobility, given the terrain that was fought in for the majority of the war in europe, would have made this weapon viable. The combined arms use of arty/smoke and tactics such that these weapons could get the drop on the enemy vehicle at 600-1000m would pay benefits. I do not see the failure of the early halftrack TDs in open tarrain, using faulty tactics as being relevant to the discussion. The germans and others would mount larger weapons in less then heavily armored AFVs just to make a mobile AT asset. The Hornet and Marders were successful stop gaps. The US was prosecuring a war of attacking and any action would draw in enemy armor.

I will again reiterate that you can not just get 17 pdrs out of thin air. The US would need to have set up a factory and get the items overseas. Getting the US tanks refurbished with 17 pdrs would have taken time also. The quickest way would have been a US Achilles (M10) conversion. Theres also training and getting ammo manufactured. And still the 17 pdr was not a weapon that could really face down panthers.

The US did mount the 90mm in a sherman as the M36B1. This was a sherman chassis with a M36 turret. Sort of half tank/half TD. But I think these were fielded very late in the war. They certainly WOULD have been welcome in summer 44. [ October 06, 2004, 04:10 PM: Message edited by: Mr. Tittles ]

Not sure where you are going but the fact remains that the 90mm using ordinary shot was better than the 17 pdr using APDS or APCBC. And it was very accurate also.

I base my assertion about APDS being unique in each gun due to this report: WO 291/762, Accuracy of APCBC/HV shot and AP/DS when fired from the 6- Pounder Gun mounted in the Churchill IV The variation of "jump" and dispersion between individual tanks is so great that an "accurate" ranging rule for applying ranges to the sight for AP/DS shooting is suggested, in effect requiring each gun to be "zeroed" individually for AP/DS aiming rather than using the same rule for all. The expected difference between the two rules is shown in this table of first-shot hit probabilities: Range (yds) Accurate ranging rule Proposed ranging rule 400 73 45 800 32 19 1000 20 14

Yes APDS is a armor piercing discarding sabot tungsten core round.

The APDS was the tungsten round? Even without Tungsten, the 17pdr could deal comfortably with the majority of German tanks at 1km+ IIRC. Since tungsten was a scarce round anyway, that doesn't really impinge on the 90%+ of rounds fired by the 17pdr. </font>

Soddball you need to read closely. I said the APDS was unstable. I have several sources. Mycenius for one. WO 291/238, The Importance of Gun Dispersion in AP Shooting. WO 291/1263, Firing Trials, 17pdr Sherman "Table VI has been constructed which shows the probability of a hit on a target 5' wide by 2' high (representing a Panther turret) at various ranges using both types of round." Range (yards) APC % AP/DS % 400 90.5 56.6 600 73.0 34.2 800 57.3 21.9 1000 45.3 14.9 1500 25.4 7.1 Comments and corrections These assume that the MPI is placed centrally on the target. The trace from the AP/DS round was not seen in 73% of cases by a flank observer, and in no case from inside the tank.

Perhaps not. I read a report that each gun would fire it differently and each gun had to find its own adjustment to using APDS. It also had a poor tracer it seems.

I point you once again to the failure of the 75mm halftrack in the desert, Tunisia 1942/43 and ask why you think a 90mm armed one would have been any more successful. </font>

The 17 pdr with APDS is so innacurate that it can be called unstable. It is accurate with APCBC ammo though. I read that 90mm weapons could target individual soldiers out to several hundred meters. One source claiming that a German helmet could be hit at that range. Most weapons of this size/barrel length when firing fixed AP ammo could cherry pick the major area regions on a tank type stationary target usually (under 1000m or so). That is, they could target the turret or hull). The 90mm AP round could hole the mantlet on a Panther at 1000 yds and penetrate the turret vertical face even further.

The war in Europe lasted less than a year. By the time the allies got ashore and the US realized that they forgot to bring a worthy AT weapon, it did not leave enough time to start manufacturing 17 pdrs in the US and getting them across the ocean in any form. The US did have 90mm anti aircraft guns and they were more powerful and accurate than 17 pdrs. To get them behind any armor so that they could back up the US tank battalions would have been worthwhile. The US M36 Jackson was not available till the Fall of 44 I believe. Any tracked 90mm weapon, even one without a rotating turret, would have been a great AT asset.

After the D Day landings and the early encounters with Panthers, the US should have realized that the only weapon that could deal with them was the 90mm. Test shoots showed the short comings off most 75-76mm weapons against the front. The US 90mm using solid shot could penetrate the hull at 600m or so and the turret much further out. The 90mm weapon should have been field modified into AFV in any way possible. Even something like a fixed mount in a converted M7 Priest would have been better than nothing.

The 17 pdr with APDS had its problems also. The ammo was extremely sensitive to each guns characteristics. That is, each barrel seemed to fire the ammo differently. The 17 pdr ammo was also very heavy. I believe it weighed (full cartridge) twice as much as 76mm HVAP). Little known is that the tracer was extremely difficult to see. Even an observer outside the vehicle had problems observing it. The US 76mm also had problems besides poor penetration (even the HVAP was marginal). The gun is described as poorly balanced and after each firing would be way off the mark. The blast and smoke made shot observation impossible under good conditions. The later use of a muzzle brake was as much for reduced blast effects as recoil.

The chin mantlet appears to be a little over 100mm thick in the most likely areas to get hit, and the irregular thickness areas may be very limited in size. The Germans tested the chin mantlet by firing a 50mm round at it, and a 100mm thickness would be consistent with the test requirements for 100mm cast armor (50mm Pzgr 39 O.K., without cap). Are you saying that they fired a 50mmL60 it it so that it would penetrate or so that it would ricochet? It would seem that a test on this improved mantlet shape would want to bounce rounds off it so as to check that indeed, the rounds are not bouncing down.

Actually a Panzer IV had both a dial 'clock' indicator AND a MIL indicator right next to each other. I suppose the clock was for roughing in a enemy target and the MiL indicator for more precise pointing. Since greater magnification sights limit field of view, this would offset the disadvantage (as long as the TC could relay the info).

I believe all turreted panzers had them. They also had gyroscopes for direction. This was so they could follow N S E W during battle.

GERMAN RESEARCH WORLD WAR II LESLIE E. SIMON Major General, Ordnance Department U.S. Army, Retired Former Director, the Ballistic Research Laboratories Far more extensive and more fundamental work was done at TAL during the period 1939-1944. Staff members conducted firing experiments against both flat and corrugated plate; they studied the way in which the ogive (the tapering head of the projectile) broke up and the manner in which the plate was penetrated. Various types of projectiles with different head shapes and of different heat treatments, different steels, and different body lengths were studied. Projectiles were fired both against single pieces of armor plate and spaced armor plate consisting of two or three pieces of armor plate with varying spaces between them. Studies were made both from the viewpoint of the defeat of the projectile by the armor plate and from the viewpoint of the defeat of the armor plate by the projectile. They studied the nature of the entry and the exit of the projectile when the plate was defeated and of the break-up of the projectile when the projectile was defeated. The movement and bending of the plate during penetration were carefully recorded and considered in connection with the mechanism of penetration. The use of spaced armor on the decks of battleships for resisting penetration by armor-piercing bombs was studied in miniature. The experimental work was carefully correlated with theoretical work. A theory of penetration was worked out which accounted for the loss of energy as a function of penetration, and which gave the force on the projectile, the friction, the force on the plate, and the effect of ring tension around the projectile as functions of the distance of penetration. For larger calibers, experimental and computed values of energy loss agreed to the order of S or 10 per cent. The results are of value in the design of fuzes, projectiles, and armor plate. Similar studies were made on the penetration of safety-glass armor plate by small bullets with steel cores. The mechanism of breaking in the successive layers of glass was studied by means of spark cinematographs. This work was applicable to the glass covers of vision slits in tanks and combat vehicles.

This is the report that rexford often cites. Notice that even the report throws out the two least accurate tanks. A unique thing is that the report suggests that each 57mm gun be zeroed or matched to APDS. That is, each gun fires the rounds differently! Even if the APDS is matched ammo, the way it leaves each gun is sufficient different that only trial and error can reveal that.

WO 291/762, Accuracy of APCBC/HV shot and AP/DS when fired from the 6- Pounder Gun mounted in the Churchill IV Trial shoots were conducted against a target 5' wide by 2' high representing a Panther turret. 5 tanks were used; the 2 with the least consistent guns are not included in the results for "3 tanks". The probability given is the hit probability of any round when the MPI is at the centre of the target. Range (yds) AP/DS (3 tanks) APCBC/HV (3 tanks) APCBC/HV (5 tanks) 500 74 89 74 800 50 84 73 1000 37 81 62 1500 20 62 42 The variation of "jump" and dispersion between individual tanks is so great that an "accurate" ranging rule for applying ranges to the sight for AP/DS shooting is suggested, in effect requiring each gun to be "zeroed" individually for AP/DS aiming rather than using the same rule for all. The expected difference between the two rules is shown in this table of first-shot hit probabilities: Range (yds) Accurate ranging rule Proposed ranging rule 400 73 45 800 32 19 1000 20 14 Comments and corrections The paper assumes that a 50% chance of a hit with any round is the minimum engagement criterion, and therefore recommends that the maximum enagagement range with AP/DS be 800 yards, and with APCBC/HV about 1000 yards.

Perhaps the 1500m was for the Tungsten round?

You must mean the drivers plate I assume? The bow 80mm armor is actually the best armor on the vehicle, especially the small sloping upper bow armor.

I just want to show the updated edit again.