M10's Against Panthers in Normandy

[JasonC]

flamingknives - the mantlet penetrations at 200m are in the tests and are well documented. Rexford cites them himself. He knows they happened. It is not possible to dispute them.

Tittles, everyone knows US 76mm encountered shatter problems against both the Panther mantlet and the Tiger front, turret and hull. The rounds broke up despite having more than enough energy to penetrate the armor. But only in a window - thus the term "shatter gap", a gap in the range of possible penetrations where expected ones routinely do not occur.

Rexford, of course there is shatter and that is why the US 76 doesn't kill through the turret front at 1 km, as I said myself previously in the thread. But they *did* kill through the turret front at 200m.

Having a few dead Panthers that we know were engaged at 200m or less that do not have holes in their mantlets does not mean, it does not imply, it does not even suggest, that shatter continued down to point blank. Explicit tests show that it did not. And so do numerous tactical engagements in which US 76mm TDs outscored Panthers when the range was close, with typically only 2 hits needed for a kill. They did not all hit the MG ball.

The Normandy engagements also show they penetrated the lower front hull when the range was close. There is nothing surprising in this. The range of the reported AP failures in the tests is longer than in the tactical engagements (400 and 600 vs. 120 to 200), and HVAP is not always better than AP against extreme angles.

The US 76mm was effective against everything but the glacis at short range. It was ineffective vs the mantlet at longer range due to shatter. You cannot turn the second of those into a denial of the first without making nonsense of actual tactical events.

[Mr. Tittles]

The tests only mention problems with AP having base detonating problems. The guys running the tests know about this shatter gap? Maybe this phenomena is actually just that. The AP piercing shells predetonating.

The action of the fuse may have been too quick. Less than the time needed to get the shell through the armor logically.

Are there examples of solid shot (non-HE) AP experiencing a range gap that shows this? An example would be penetrating at close range, not penetrating at a longer range, and then penetrating again?

[Mr. Tittles]

17pdr APCBC 800 yds 120mm - PTP (complete penetration)

120mm RHA at 30 degrees

Again, this weapon shows that a Panther turret front should be no problem at 800 yards. Thats the Mantlet and true turret front.

I base this on:

1. RHA is tougher than cast armor

2. 120mm is supposedly thicker than panther mantlet

3. 30 deg angle would correspond to not only apex of cast mantlet but also extend this area.

I know I have read of two 17 lbr shoots in the field (APCBC). One described the glacis as being inpenetrable and the turret being pierced at 300 meters or so. The report mentions sherman 75mm needing a very lucky hit on the lower mantlet.

[ January 08, 2004, 03:35 PM: Message edited by: Mr. Tittles ]

[JasonC]

The 17 pdr was powerful enough, it did not face shatter problems against either the Panther mantlet or the Tiger front. The 75mm was too weak to get through either. The shot trap on early model Panthers was an exception but completely unrelated.

The US 76mm had enough penetration that by the measured equivalences for armor thickness and slope, it should have penetrated either out to medium range. That is why the US ordnance department thought it would be sufficient against the German heavies, and was not prepared for the demand for tungsten rounds they actually ran into.

In the field it was found that the US 76 only sufficed at close range, or when using tungsten ammo. At medium range the shells broke up. When overpenetration reached about 1.2 to 1.25, they succeeded again. Tests against captured tanks rather than theoretical calculations confirmed the problem. And led to an increase in tungsten supplies on the one hand, and acceleration of deployment of 90mm TDs on the other.

None of this is in dispute. It is the backround on which Rexford is making two additional claims, which go far beyond any of the above, painting the Panther as essentially "proof" against the US 76mm from the front, regardless of range.

He wants to infer, first, that shatter problems continued clear down to point blank, despite known test evidence directly to the contrary. He wants to infer this from an absence, not any actual observation - that a small sample of dead Panthers killed by US 76mm have their holes elsewhere. This is not a legitimate inference.

He wants to infer, second, that the lower front hull could be penetrated only when it was thinner than spec. Despite the fact that the dead tanks *not* killed through the mantlet, that he just cited for the previous, *were* killed through the lower front hull.

Rexford has no actual evidence that those lower front hulls - the ones in Normandy with US 76mm holes in them, that we know were actually made by plain AP at 200m or less - were thinner than spec. He just "wills" it to be so. All he can say in favor of it is that the same tests that showed no shatter problems at close range - that he just implicitly dismissed in the previous case - showed some ricochets from the lower front hull at longer ranges - and in several cases using different ammo (HVAP) - than occurred in the Normandy engagements in question.

He says the lower front hulls in those tests also measured above spec (spec was 60mm). Which to anyone not biased for invulnerable Panthers would suggest that it is utterly unsurprising that lower front hulls only as thick as spec - 60mm - and at a closer range - 120 to 200 yards, rather than 400 plus in the tests - were in fact penetrated by the US 76mm.

It requires a real pro-German bias pretzel, however, to infer from two sets of holed Panthers - one in the tests with mantlet holes made at 200m, and another in the field in Normandy with lower front hull holes made at 120-200m - that neither the mantlet nor the lower front hull were penetrable by the US 76mm.

It is not all that complicated what is going on. Rexford has simply decided that Panthers are sexy and therefore should be as invulnerable as possible. Since 75mms already bounce and it would be too ridiculously ahistorical to claim 17 pdrs do, he lobbies for invulnerability to US 76mm.

He then looks for any scrap of minutae that straining at a gnat and swallowing a camel can construe as leading to invulnerable Panthers, and posits as many hypothetical varieties of Panther and of ammo and of conditions and of random variations as are necessary, to avoid manifest direct contradiction of known empirical cases.

Whenever a shell penetrated, it was a special magic shell that cannot be expected most of the time. Or a special paper-thin plate instead of a real one. He multiplies Panthers endlessly to wave away all the known dead ones. This quite simply is buncomb. The fact that Rexford has done fine work in this area in the past, is here being traded on by him to extend his pet bias.

I've said my piece on the subject. To avoid further pointless or personal controversy, I will now give it a rest.

[ January 08, 2004, 07:56 PM: Message edited by: JasonC ]

[Mr. Tittles]

Curved surfaces distribute stress better than sharp-cornered welded

boxes, so curved mantlets acted a bit thicker than their weak granular

structure would lead us to expect. That is, they were kinda the same as

if they were RHA.

From..

http://yarchive.net/mil/ww2_tank_armor.html

[Mr. Tittles]

7) 3-inch Gun, M5, mounted on Motor Carriage, M10

a) APC M62, w/BDF M66A1 will not penetrate front glacis slope plate at 200 yards. Will penetrate gun mantlet at 200 yards and penetrate sides and rear of the 'Panther' Tank up to 1500 yards.

AP M79 will not penetrate the front slope plate or the mantlet at 200 yards. It holds no advantage over APC M62 ammunition w/BDF M66A1.

So the M79 round does not penetrate the mantlet at 200 meters.

[rexford]

"There ARE failures in these tests from the base HE going off prematurely by the way.

I think a better question is why is penetration of the cast mantlet such a problem?

The only shatter data you show is point blank range? How is that a 'gap'?"

=============================================

Base HE burster going off was problem with 90mm APCBC, not 76mm.

Penetration of the Panther cast rounded mantlet was not a problem as I previously showed by reference to British firing tests against Panther mantlet. If 6 pdr APCBC penetrates Panther mantlet well beyond 500m then the U.S. 76mm APCBC should, too.

The British firing tests show that it is silly to assume that a rounded mantlet has superior resistance qualities, no truth to that at all.

Penetration of the rounded cast Panther mantlet may have been a problem for 76mm APCBC due to shatter gap tendencies.

It's a shatter gap because the tests used velocities above and below the muzzle velocity and there is a range of velocities where it fails surrounded by velocities where it succeeds. A gap in the penetration results.

When a person quotes Wa Pruf penetration range estimates as proof of anything they should keep in mind that those figures were usually calculated from available data, and assume all sorts of impact angles. The penetration data is sometimes wildly inaccurate, and the armor may or may not be adjusted for cast armor deficiency, high hardness problems, poor quality or whatever.

It was also a standard procedure to use a 30 degree side angle on many of the penetration range calculations, or to assume a 30 degree hit on a rounded piece of armor.

One calculation has Panther hits on the T34/85 glacis failing beyond 800m.

In other words, Wa Pruf penetration range data proves nothing and is sometimes inconsistent with actual firing tests.

Lorrin

[ January 09, 2004, 07:50 AM: Message edited by: rexford ]

[rexford]

"7) 3-inch Gun, M5, mounted on Motor Carriage, M10

a) APC M62, w/BDF M66A1 will not penetrate front glacis slope plate at 200 yards. Will penetrate gun mantlet at 200 yards and penetrate sides and rear of the 'Panther' Tank up to 1500 yards.

AP M79 will not penetrate the front slope plate or the mantlet at 200 yards. It holds no advantage over APC M62 ammunition w/BDF M66A1.

So the M79 round does not penetrate the mantlet at 200 meters."

The AP M79 outpenetrates the U.S. 76mm APCBC by about 25mm at 200 yards and does not have an HE burster so the failure cannot be related to base HE detonation.

Why does 3" M79 AP fail against the Panther mantlet at 200 yards but the 76mm M62 APCBC with less penetration succeeds?

Why does 76mm M62 APCBC fail against the Panther mantlet beyond 200 yards when it has 100mm rolled armor penetration at 1250m? And don't say the rounded mantlet is superior to a flat plate cause the British tests say it ain't so!

[ January 09, 2004, 07:55 AM: Message edited by: rexford ]

[Mr. Tittles]

The Panther Mantlet is a curved surface. Unless you hit it within a very dead-on strike against the most vertical part of the curve, results will vary.

Since there is penetration data for the M79 round, it obviously was shot at target plate at ranged targets before being fielded. The shatter gap did not show up? How do you explain this? variations in shot, plate, etc?

[Mr. Tittles]

4. On 14 Oct the 17 pdr tks saw their first action when this sqn provided close sp for an inf bn (H & PE) in an advance beyond SCOLO RIGOSSA. In the first afternoon this force gained approximately 1500 yds against stubborn resistance. Although the 17 pdr tks were kept rearmost in their tps, they were called upon to shoot up many houses and dug-outs, and the HE shell was found to be about the same as the 75mm. In the opinion of one tp sgt it "seems to knock out the back wall of the house"

5. An opportunity to observe its hole-punching capabilities came late in this first afternoon. One of the tp cpls spotted a Panther at about 300 yds range. He indicated it to his tp sgt and meanwhile fired one round of 75 mm AP at it. The tp sgt's gunner reports that as he laid the 17-pdr on the Panther, its turret was swinging slowly towards him and, as be fired, was still roughly 30 degrees off. Four rounds of 17-pdr AP were fired, all scoring direct hits. The Panther did not brew up, our own inf patrols, fearing recovery by the enemy, set fire to it during the ensuing night.

6. The remains of this tk may be seen at BULGARIA (mr 656045). There are two clean holes in it and three "gouges". One hole is in the side of the gun barrel, approx 3 in from the mantlet; since there is no hole out the other side of the barrel, and judging from the angle of penetration about 60 deg from normal) it seems probable that this AP round entered the turret via the breech of the gm. The other hole is in the side wall of the turret."

http://web.inter.nl.net/users/spoelstra/g104/firefly-i.htm

Not exactly conclusive but interesting none the less. Would be interesting to know where the gouges were.

[Mr. Tittles]

Another fact that helped the Tigers a lot was the "shatter gap" effect which affectted allied ammunition, a most unusual situation where rounds with too high an impact velocity would sometimes fail even though their penetration capability was (theoretically) more than adequate. This phenomenon plagued the British 2 pounder in the desert, and would have decreased the effectiveness of U.S. 76mm and 3" guns against Tigers, Panthers and other vehicles with armor thickness above 70 mm. It should be noted that the problems with the 76 mm and 3" guns did not necessarily involve the weapons themselves: the noses of US armor-piercing ammunition of the time turned out to be excessively soft. When these projectiles impacted armor which matched or exceeded the projectile diameter at a certain spread of velocities, the projectile would shatter and fail.

Penetrations would occur below this velocity range, since the shell would not shatter, and strikes above this range would propel the shell through the armor whether it shattered or not. When striking a Tiger I driver's plate, for example, this "shatter gap" for a 76mm APCBC M62 shell would cause failures between 50 meters and 900 meters. These ammunition deficiencies proved that Ordnance tests claiming the 76 mm gun could penetrate a Tiger I's upper front hull to 2,000 yards (1,800 meters) were sadly incorrect.

http://www.fprado.com/armorsite/tiger1.htm

[Mr. Tittles]

I have read of one other British target shoot on Panthers. It was an excerpt from a Unit history. It was published in a Panther book (Uwe Feist?).

The Panthers had been KO'd the day befoe from the side. The unit then did a field shoot from a distance and progressively moved the shooters closer till results were obtained. The shooters were sherman 75mm and Firefly.

The results concluded that 75mm had just the slim chance of getting the mantlet bounce. The 17 pdr could hole the turret front (meaning the mantlet, turret front I take it). At 300 meters. The hull was, of course, tougher.

This was during the Normandy battles when Panthers were first encountered.

[Mr. Tittles]

http://www.warships1.com/index_tech/tech-085.htm

I assume this is the report rexford is citing.

[ January 11, 2004, 05:16 PM: Message edited by: Mr. Tittles ]

[Mr. Tittles]

From earlier website..

5) 57mm Gun, M1

a) APC, M86 will penetrate the sides and rear of the 'Panther' Tank at 1500 yards.

Sabot fails to penetrate front glacis slope plate and gun shield at 200 yards. Due to difficulty experienced in obtaining hits no conclusion as to the effectiveness of this ammunition was reached.

Sabot fails at 200 yards? can sabot have shatter gap?

Heres another test shoot, kind of wierd..

http://www.100thww2.org/support/77657mm.html

I say wierd because it claims penetrations of the turret front. It does not specify location exactly, then cocludes that breaking tracks when the Panther faces you is the best bet.

[rexford]

Originally posted by JasonC:

Having a few dead Panthers that we know were engaged at 200m or less that do not have holes in their mantlets does not mean, it does not imply, it does not even suggest, that shatter continued down to point blank. Explicit tests show that it did not. And so do numerous tactical engagements in which US 76mm TDs outscored Panthers when the range was close, with typically only 2 hits needed for a kill. They did not all hit the MG ball.

The Normandy engagements also show they penetrated the lower front hull when the range was close. There is nothing surprising in this. The range of the reported AP failures in the tests is longer than in the tactical engagements (400 and 600 vs. 120 to 200), and HVAP is not always better than AP against extreme angles.

The US 76mm was effective against everything but the glacis at short range. It was ineffective vs the mantlet at longer range due to shatter. You cannot turn the second of those into a denial of the first without making nonsense of actual tactical events.

Jason,

You are so wrong and continue to either ignore or fail to understand a simple statement I made which is supported by fact.

Panthers were built with 50mm and 60mm front lower hulls. At Isigny the U.S. 76mm APCBC failed against the 60mm lower hull front at close range, and so did 76mm HVAP on 2 of 3 hits at close range.

Turns out the 60mm design thickness was actually 67mm on one of the Panthers where they measured.

When a Panther had a 50mm front lower hull, as many did in the Normandy battles, then an M10 hit with APCBC would penetrate at close to medium range.

Continue to ignore the above facts and I'll just have to ignore your garbage in the future.

U.S. Navy tests show that 76mm APCBC could shatter fail against 97mm of rolled homogeneous armor at close to the muzzle velocity, which suggests that hits on the Panther mantlet at 200 yards could fail in certain circumstances.

Now that I think about it I'am not going to continue to repeat the same stuff in response to your nonsense, and argue with you. If you don't want to face facts, that's your problem.

Lorrin

[ January 11, 2004, 11:34 PM: Message edited by: rexford ]

[c3k]

Whoa!!

Look at this from Mr Tittles. (Parts omitted for brevity.)

Originally posted by Mr. Tittles:

From earlier website..

(Parts deleted.)

Sabot fails to penetrate front glacis slope plate and gun shield at 200 yards. Due to difficulty experienced in obtaining hits no conclusion as to the effectiveness of this ammunition was reached.

(Parts deleted.)

Okay, with all this talk about weak spots and all, how do you miss your aimpoint at 200 yards? This is , after all, a controlled shoot with no incoming fire.

Difficulty obtaining hits at 200 yards. That is important.

Thanks, Ken

[Mr. Tittles]

Sabot rounds in both the 6 pdr and 17 pdr were noted to be innacurate.

[c3k]

Yes, I know the early sabot rounds were inaccurate, but a flintlock can hit a target at 200 yards (not well, but it CAN). That's not inaccurate, that's a crapshot. Literally.

Ken

[Mr. Tittles]

The precision needed to hit the 'flat' part of this curved surface is greater than it might appear. In the process of hitting the surface, and missing, you damage it and muck up the test.

The surface can be represented as circle when viewed from the side. It rapidly changes slope as hits are distributed up and down the surface. If a formula for a circle is written and a derivative taken (showing the tangent) then it can be understood mathematically.

The precision to hit the mantlet at 200 yards is probably achieved but the precision to hit the particular 'strip' needed is not.

[Jack Carr]

Originally posted by JasonC:

Quicker vehicle - to fire, more than road speed movement. It was the sighting differential and resulting first shot that usually decided the really short range shoot-outs. On the attack, the Germans were often inside the US defensive zone, and often stripped of their infantry already. They were typically buttoned. The open TDs found it easier to see them, and probably to hear them too.

Lehr's counterattack in mid July -

"in position about 300 yards east of le Desert on the road to la Perrine, attacked three tanks which had penetrated the American lines for 500 yards. During a fight in which one American TD was knocked out, one of the enemy tanks was destroyed and the other two were forced to withdraw after being set afire.

To the west of le Desert, approximately ten German tanks drove north on the unimproved road leading from the le Hommet-d'Arthenay crossroads to la Charlemenerie and succeeded in reaching a point just south of la Scellerie. Here the column was stopped when the 3d Platoon, Company A destroyed the leading German tank after losing one of its own M-10's. To deal with the German threat in this area, the Company A commander reorganized his tank destroyers and requested a company of infantry as reinforcements. While awaiting the arrival of these troops, the TD's spotted three Mark V tanks on the road west of la Scellerie and opened fire, destroying with 12 rounds the tanks and one half-track.

Later in the morning, Company C, 899th Tank Destroyer Battalion, holding positions near la Charlemenerie, knocked out its first German tank of the campaign. A well-camouflaged Mark V, carrying several soldiers and accompanied by others on foot, rounded the west corner of the crossroads below la Charlemenerie in front of an American tank destroyer. The M-10 opened fire and with two shots destroyed the German tank, killing and wounding several crew members and scattering the rest.

Another Panther thrust in the early afternoon toward la Charlemenerie, near the la Caplainerie road junction, was stopped by two of Company C's tank destroyers with the aid of Company F, 32d Armored Regiment (Combat Command A). The Company F tanks were located in orchards on either side of the road waiting to take part in a 47th Infantry mission, while the two M-10's were holding positions on the road about 200 yards from the American armor. As the Mark V's appeared, Company F opened fire with HE at a range of 400 yards. The Panthers continued to roll, however, and the leading tank broke through to fight a duel with an M-10 at a range of 120 yards. The Mark V was damaged by TD fire, but it returned a shot, hitting the TD and wounding or killing three members of the crew. The other M-10 then opened fire, finishing the Panther with two shots. Then, spotting another Mark V, the TD fired ten rounds into the suspension system of the Panther, which sideslipped helplessly against the bank on the east side of the road and hung there in a tangle of matted hedgerow and churned mud. The crews, who had left their tanks when they were hit, were tracked down by infantry and captured in a farmhouse in the vicinity.

The slaughter of the German armor continued. As the 1st Battalion, 47th Infantry moved down the road west of la Charlemenerie to contact the 3d Battalion, the first two M-10's in the column spotted two Panther tanks approaching from a lightly wooded area to the left front. Before these tanks could get into action, the TD's opened fire with their 3-inch guns at a range of 170 yards, knocking out both Panthers. A few moments later a third Mark V was discovered on a farm road to the east. Both M-10's fired on it, and ten minutes later this third tank was found pitched inert against a hedgerow. None of the enemy tanks had been able to fire on the 1st Battalion before being hit.

In sum the enemy armor had floundered helplessly after its breakthrough."

That TD unit killed 12 Panthers and 1 Pz IV for a loss of 3 M-10s. As the narrative shows, the range was typically 120-200 yards, at most 400 on first sighting. The Germans often did not get a single shot off. Sometimes they survived the first hits and killed 1 M-10, before losing the engagement.

The best the Panthers managed in the Arracourt fighting was an even exchange with M-18s they ran onto in fog. In other places in August and September, fresh brigades were cut in half inside 48 hours, taking fewer plain Shermans with them than they lost Panthers - let alone upgunned TDs.

On defense with long open lanes of fire the Panther could be a very effective tank killer. But charging into the enemy defense both blinded them, and exposed their thin sides if the ground was open. While Allied TDs (and for the Brits, Fireflies) could stop pure frontal moves where the flanks were covered, in thick terrain, from positions with short LOS lines.

If they had been nearly invulnerable from the front even at close range they would have been terrors in the hedgerows. They weren't. The head of Lehr talks about what a waste it was to attack with them in that terrain.

"Bayerlein attributed the result of the day to the exhausted condition of his men when they entered battle, and to the difficulty of operating Mark V tanks in the hedgerows. He declared that his armor had to fight at maximum ranges of 200 yards because hedges concealed everything farther away. He could not use the Mark V's for cross-country movement."

There was another very good book on this subject "Panzers in Normandy". Has excellent first hand accounts from both sides and really explains exactly what the German tanks were up against. There was one particular instance in which the Germans counter-attacked into a town with a group of Panthers, I believe it was a 12th SS unit, and they got their heads handed to them. When you hear so much about how great Panther and Tiger were compared to their Allied counterparts and then you read accounts of what occurred you wonder who had the better vehicle for the type of fighting and terrain.

[Mr. Tittles]

I think that there are many variables here and possibly many failure modes.

1. Velocity variations. If a gun would produce a considerable velocity variation, than a narrow penetration gap would appear. This would be intermittant.

2. Decapping. Shatter gap in this case is then explained by cap failure. Under certain conditions, the cap does not protect the penetrator and the penentrator shatters.

3. Large base HE predetonating (90mm but if you read the reports, they want to possibly use all inert ammo for all AP)

4. variations in armor. Thickness, quality, type..

Its unbelievable that Tiger I shoots were not done with US ammo prior to D Day. Sicily? Italy? There must be data.

My opinion is that these field shoots are the best 'snapshot' data. It gives the wargame designer a real performance characteristic and supposed range data can be interpreted to the field data.

[flamingknives]

Originally posted by c3k:

Yes, I know the early sabot rounds were inaccurate, but a flintlock can hit a target at 200 yards (not well, but it CAN). That's not inaccurate, that's a crapshot. Literally.

Ken

Consistantly hitting a target at 200yds with a smoothbore flintlock is quite impressive.

The problem with early APDS is that the sabot didn't separate cleanly, so if you have your penetrator with an asymmetric lump stuck on it for even a fraction of a second it will veer wildly.

[Mr. Tittles]

This problem could effect HVAP also. If the dense center is not axially balanced, or there is a difference in the surrounding material balance, then it will lose accuracy. The US, at least, made the most accurate HVAP from reports. The US did not prodice APDS in time for WWII in ETO but supposedly, it was also accurate.