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.

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 ]

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.

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

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.

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?

TABLE 5.—Hit probability for human targets, Japanese grenade discharger and mortar shells Distance of panels from burst (radius of circle in yards) Probable number of hits for type of shell yards**Type 89 grenade discharger, 81 mm. 90 mm. 5 ***********1.56 4.4 5.7 10 ***********.39 .55 .7 15 ***********.17 .16 .21 20 ***********.10 .07 .09 25 ***********.06 .04 .05 30 ***********.04 .02 .03 This data shows the grenade discharger outperforming the 81mm from 15 yards outward. I would interprete this to mean the small shell had a rather efficient fragmentation. The nature of these hits, or qualitative value, would depend on the size/velocity of the fragments which the test does not specify. The test statically fired these shells on the ground, in a vertical orientation, with the nose buried one inch into the ground. Not a bad test but possibly the velocity of the round (or even spin in rifled examples) might also be factors. [ January 11, 2004, 10:00 AM: Message edited by: Mr. Tittles ]

TABLE 5.—Hit probability for human targets, Japanese grenade discharger and mortar shells Distance of panels from burst (radius of circle in yards) Probable number of hits for type of shell Type 89 grenade discharger 81 mm. mortar 90 mm. mortar 5 ***********1.56 4.4 5.7 10 ***********.39 .55 .7 15 ***********.17 .16 .21 20 ***********.10 .07 .09 25 ***********.06 .04 .05 30 ***********.04 .02 .03 The reader should note that this was just one test. Under different circumstances, results could also be expected to differ. For example, a mortar shell does not hit the ground perpendicularly when fired for effect. The more acute the angle a shell assumes when striking the ground, the more the distribution of fragments will vary from pure randomness in all directions. Those emanating from the upper surface will go high into the air, those from the sides will come closest to a random dispersion within limited bilateral areas, and those on the underside of the shell will imbed themselves in the ground. This results in a butterfly pattern of dispersion which is ascribed to many types of shells. While the foregoing experiment arrived at some figures for the dispersion of fragments from these Japanese missiles, it did not tell what the wounding capabilities of the hits were. This is the core of the subject of wound ballistics and will be fully developed in later chapters of this volume. Neither could the study just described determine by actual count the number -------------------------------------------------------------------------------- 25 of fragments produced by each type of shell. Of the fragments which were recovered, their size was generally small, about one-eighth to one-sixteenth of an inch in diameter. A study conducted in the Zone of Interior in December 1944, however, had as its purpose the recovery of as many fragments as possible from the detonations of each of five 81 mm. mortar shells. From 542 to 696 fragments per shell were recovered. The mean was 608.6 fragments per shell. This corresponds remarkably well with the sum of the entries in the column pertaining to the number of hits for the 81 mm. mortar calculated for full coverage of circles in table 4. Figure 11 shows the number, size, and shape of the fragments recovered from one of the five shells tested. FIGURE 11.—Fragments recovered from Japanese 81 mm. mortar shell exploded under test conditions in Zone of Interior in December 1944. -------------------------------------------------------------------------------- 26 The foregoing studies were presented to give the reader an appreciation of the wounding potential of Japanese mortar shells as he reads subsequent chapters of this volume. It would have been desirable to note the initial and terminal velocity of the fragments and their weight, since the actual wound production of a missile is, to a great extent, a function of its mass and velocity. These data were not available, unfortunately, but it can be assumed, based on the initial velocity of fragments from other mortar shells of similar properties, that the initial velocity of fragments from the Japanese 81 mm. shell was over 2,500 f.p.s. The weight of the fragments of the Japanese 81 mm. mortar shell can be estimated in that the average gross weight for one shell of fragments collected from detonations of the December 1944 test was 5.50 pounds. Thus, it took more than 100 fragments of the Japanese 81 mm. mortar shell to make 1 pound of steel. These data, taken in conjunction with the distribution data presented, should give the reader a good idea of the value of the mortar in ground combat—a weapon which was so fully exploited by the Japanese. The German 81mm fragments were greater in number. Notice the chance of catching a fragment in the chart. The Japanese 81mm does not have the intense 'peppering' effect of the German 81mm. The Japanese 81mm would have an extended danger zone also. Notice the probability falloff too. Theres a 1 in 14 chance at 20 yards. theres only slightly more than half a chance at 10 yards! [ January 10, 2004, 09:58 AM: Message edited by: Mr. Tittles ]

Here is a cutaway of a Japanese 81mm mortar shell. Notice the thin walled construction, large HE mass. The front of the shell would produce large fragments and these would be blown strait into teh ground. Heres the same shell fragmented.. [ January 10, 2004, 09:46 AM: Message edited by: Mr. Tittles ]

I did some quick math and took the large and medium fragments (~2000) and divided them into a half spherical shape of 10 yards (you mix yards and meters by the way) radius. This gives about 3.2 peppers per square yard. Since mortars do fan the spray close to the earth and not spherically, I assume a spray about 25-35 degrees. So tripling it gives 9-10 peppers per square yard. A standing man probably is about a square yard so he would catch multiple casualty causing fragments even at 10 yards (note:even if standing he would only be in about 11 degrees of the 30 degree spray, even this close, so always duck when mortars drop on you). Closer to the impact would be deadlier with all the small fragment group and blast from the HE adding in. But the further away, the less spray. The angled spray would largely miss a standing man at 20 yards. Perhaps 3/5-4/5 going over his head. The middle group of fragments also loses steam and the small fragments (which were just extra shredders inside the 10 yard radius anyway) are useless. The odd chance of being struck at 80 meters (even the large group of fragments is losing steam) is overstated by JasonC. The density of fragments is very small considering angular spray. This extension of casualtys is really a hindrance since its more a threat to attacking friendly troops in most cases. I would characterize the kill zone to be around 5-6 yards, 100% casualty zone around 10-12 yards, and reduced casualty zones extending to about 40 yards. Danger zone would be to 80 yards or so. Some mortar shells like the US 81mm heavy and 4.2 inch did have a cylindrical shape and would put out a great amount of fragments nearly parallel to the ground. But the real important question is: How effective is the fragmentation of the mortar shell? It may actually be pretty damn good. I tried multiplying the average size (taking the endpoints of the range of masses and dividing by two) and then multiplying by the number of fragments in that range. The total mass is greater than the empty mortar shell mass but it gives a general idea. The large fragment size group (arguably the most effective), may account for close to 2/3rds the mass of the shell. The middle fragment group possibly slightly less than a 1/3 and the small group maybe 5% or so. Not bad really. The waste group, the smallest, does not represent that much of the mass of the shell. [ January 10, 2004, 09:31 AM: Message edited by: Mr. Tittles ]

Uh, its a trick question to see if anyone is paying attention. The fact is, again, its the price you pay. Just like the pretzels, theres waste. Ideally, we might want the mass of the shell to blow into fragments all within a narrow size range with identical velocitys and a well defined casualty zone and safety zone. But the reality is that we want the most MASS to fall into an acceptable RANGE and take the big and the small with it. So the result is that we have a small kill zone and a large danger zone. Not exactly optimal perhaps. A larger kill zone with a smaller danger zone being prefered. This data fixates on fragments per pound but it should really fixate on effective fragments per pound. 40% of the fragments fall into the small fragment size group (really overkill in the sub-10 yard range and swarf). It would be nice to know the mass percentage of the shell this represents. [ January 11, 2004, 09:56 AM: Message edited by: Mr. Tittles ]

This data is very useful. Its the german 81mm mortar bomb. The gray areas show fragments below a casualty causing threshold. The horizontal lines give velocity spreads with the small vertical tick showing the mean. A general statement is that much of this cast iron bomb has been blown to very small particles. Many of the small particles are just wasted. A case of too much HE, too thin a wall and too weak a material (cast iron)? [ January 09, 2004, 01:42 PM: Message edited by: Mr. Tittles ]

Since I love to share (unlike certain Germans who won't even translate pantherFiebels for us)... http://history.amedd.army.mil/booksdocs/wwii/woundblstcs/default.htm This is a great resource. But some of the data includes very graphic pics of corpses. Here is the webpage with the best data http://history.amedd.army.mil/booksdocs/wwii/woundblstcs/chapter1.2.htm [ January 09, 2004, 01:32 PM: Message edited by: Mr. Tittles ]

General comments about the fragmentation of these two projectiles: 1. Mortar round has more uniform size distribution. This is because of the more spherical shape ('bomb' body) compared to the cylidrical shape of the 50mm shell. Mortar rounds typically are thin walled and have a high HE percentage by weight. The tail section typically is blown off in one piece and is shot vertically (back up). They come down again and are not a casualty causing mass typically. 2. The 50mm shell is greater in mass (or mass under HE effect). The 50mm shell rear cap broke off into a round piece. Large sabers are evident. So which is more deadly in CM terms? If there is any doubt about the German 75mm HE shell being VERY deadly, than look at this...

Heres a 50mm gun HE round (50mmL42 or L60) that has its fragments recovered. Remember the pretzel test?

Heres a 50mm mortar round that has most of its fragments recovered.

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.

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

This pic shows troops waiting to board a C47. They have the rifles intact.

The M1 Garand was supposedly broken down and carried. It was reassembled on landing. The M1 Carbine had a special holster and was not broken down.

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 ]

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?

Depends on what you're using it for. The BAR suffers the same drawback as the MG-42... it drops in a canister. The FG42 was light and small enough to be carried by the para when he jumps. The big lesson the Germans learned from Crete was that they needed firepower as soon as they hit the ground. So, when the went into Leros, they went armed. The Kar98's and MG42's still went in canisters, but the men jumped with MP40's and FG42s </font>

76mm Shell, APC M62 500 yds 100mm no PTP This data is from shooting at a test plate 100mm thick 30 degree slope RHA. The US 76mm achieved a complete penetration at 500 yards. Now, you are saying the Panther mantlet is 100mm cast armor. If hit at the apex; why does it have to be 200 meters? If it penetrates (completely) at 500 yards a plate of angled/better quality, why is it having such a problem with cast armor and needs a shorter range? I am assuming that the shoots started at a certain range and as no penetrations occurred, they moved the firing weapon closer. Is there other data that supports shatter gap against cast armor for other guns/targets? 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'? [ January 08, 2004, 10:18 AM: Message edited by: Mr. Tittles ]

Is that an official request? </font>