Canister in CMBB: Realistic or Hollywood?

[c3k]

Gentlemen,

Thank you for taking the time to point out the flaw in my thinking - and doing so politely. I shall now shuffle back to my seat in the back corner and refrain from raising my hand for the rest of class.

Thanks,

Ken

[Jeff Duquette]

Shrapnel casing does shatter upon detonation of the base charge. Examples of Russian 76.2mm Shrapnel shells exploded within some sort of enclosed sand-box and the shell casing fragments and shrapnel pellets subsequently collected and recorded can be seen in the following.

http://www.geocities.com/tigervib_2000/Russ_76mm_Shrapnel_003a.jpg

(copy and paste above url into your browser address box...hit enter to view the image)

An 11-gram shrapnel pellet is about 170-grains. The original Colt cartridge accepted by Army Ordnance was a 230-grain round nose bullet. Muzzle velocity was about 830-fps, or about 253-m/s. The original 45 auto round nose is actually a much more efficient ballistic shape than the pseudo-spherical shrapnel pellet. Bear in mind that the original reference by LTC Bishop to shrapnel and the 45 pistol was to give the reader a ball park indication of shrapnel capability. In my mind it wasn’t intended to read: "45 round nose capabilities = ½-inch shrapnel pellet capability".

Moreover velocity decay rate of the 45 round nose is much less with range than the rate of velocity decay of a shperical shrapnel pellet. Cd in the subsonic range for the round nose G1 projectile is about half that of spherical shrapnel. In other words, all things being equal the impact energy relative to range of the 45 slug will decrease at a much lower rate than the shrapnel ball.

LTC Bishop goes on to indicate that the fully loaded standard issue WW-One US ARMY pack of the period (a monstrous contraption) was capable of stopping lower energy shrapnel pellets. Bishop suggested that the best thing for infantry men to do when under shrapnel fire was to either A: get under cover or out of the vicinity, or if you can’t do “A” than B: lay down on your belly with your ass facing the direction of shrapnel fire. Your helmet and pack will provide “some” degree of protection.

Lighter bullets have since been produced for sportsmen using the 45 auto. Speer used to make two 45 Auto jacketed semi-wadcutters weighing in at 185-grains and 200-grains respectively. Both rounds were reputed to be very accurate bullets (by Speer ;o). In addition the BC of the Speer 45 jacketed semi-wadcutter is about half that of the round nose.

Regarding helmets…I have always been under the impression that steel helmets drastically reduced the numbers of head wounds resultant from low velocity\low energy shrapnel and shell fragments.

I have seen a circa-1943 training film on US Army Small arms (I watched part of the tape again this morning). “Training Film TF-7 1266, War Department, Army Ground Forces, Infantry Weapons and their Effects”. The film snippet of the 45 pistol shows the 45 round nose incapable of penetrating the German WWII steel pot. The helmet is perched on the head of an unfortunate Nazi mannequin. The films narrator indicates: “Beyond 50-yards the 45 will not penetrate even light armor.” Again bear in mind that impact energy of shrapnel will decrease with range from burst at a much higher rate than that of a 45 round nose. Presumably at point-blank or very short ranges the .45 slug might punch a hole through a German steel pot.

On the grander scheme of things a massed shrapnel barrage could be very effective against troops in the open. Shrapnel was originally designed as a projectile to combat somewhat dense infantry formations in the open. These were the sorts of targets that an artillerist might expect to see during the Franco-Prussian War, Russo-Turkish War, Russo-Japanese War, or on early 1914’ish WWI battlefields. On the other hand shrapnel was not particularly effective against entrenched troops ... even light field works.

Also within the grander scheme of things, I don’t think massed shrapnel barrages can be compared to single rounds of shrapnel fired in a self-defense role; pseudo-canister. Slop in fuse accuracy is somewhat masked during massed tube barrage fire. However a single tube firing shrapnel with questionable fuse accuracy and/or questionable crew training might result in that hoped for pseudo-canister effect of a shrapnel round not occurring till the round is some 200 or 300 feet down range from the intended target.

[ June 07, 2003, 07:21 PM: Message edited by: Jeff Duquette ]

[John Kettler]

Jeff,

Excellent points and yet more incredible resources unearthed! It appears I misunderstood what I saw in excerpts from that same film aired on the History Channel in the U.S. or that we saw two different pieces of film, a possibility I consider unlikely. I don't remember any narration on the segment I saw, but I distinctly remember the Stahlhelm's being shot off a German uniformed mannequin peeking out around a tree trunk. Though I would've sworn the shot holed one side and knocked the helmet off, apparently that "piercing" was supplied by my own interpretation of what I saw.

Do we have any black powder enthusiasts out there who own an old style Colt .45 percussion revolver or replica which fires spherical lead projectiles? If so, what is the muzzle velocity for that load and what is the weight of the ball, please? Jeff, I find your projectile shape argument to be compelling, hence am trying another approach.

Regards,

John Kettler

[ June 07, 2003, 07:58 PM: Message edited by: John Kettler ]

[Jeff Duquette]

Have no fear John. You are probably not suffering from an early form of Alzheimer’s. Your memory cells are likely calling up the results of the M1 Garand being cut loose against the same Nazi mannequin (still sporting a steel helmet).

The training film I am referring to (and presumably sliced into interesting bits for the History Channel Program you refer to) goes on to demonstrate rifle fire against the German steel pot. The Garand’s Caliber .30 M1 Ball had an approx 172-grain boat tail bullet (allowable tolerance was 171.5 to 174.5 grains). It is my understanding some of the older .30 M1906 ball ammunition -- 150-grain bullet -- was also employed by the Garand. Muzzle velocity at standard conditions was 2,700 fps and 2,647 fps respectively for the 150-grain ball and 172-grain ball. About 823 m/s and 807 m/s. Well into the supersonic range...compared to the 0.45 cal round nose that never really even approaches transonic velocities.

“Ball” is sort of a misnomer; a historical hold-over from days of yore. The M1’s “ball” ammunition actually has a bullet with a fairly pointy ogive. M1 ball is a much more “ballistically” efficient shape than the 0.45-Cal pistols round nose, and light years ahead of spherical shrapnel pellets. Anyway the training film shows the Garand’s ball ammunition cleanly punching holes through both sides of the German Steel Pot as well as the uber-mannequins head. Plenty of kinetic energy seemed to remain in the round even after passing through all of this material.

The training film than goes onto to demonstrate the Garand’s .30 AP round capability. AP round being ~168.5 grains and 2,775fps muzzle velocity. The AP round punches clear through a 6 or 8 inch diameter tree and still has sufficient energy to pass through both sides of a steel bucket filled with water placed on the opposite side of the tree. This was probably pretty scary news for the average tree hugging infantryman watching this flick.

[ June 07, 2003, 10:22 PM: Message edited by: Jeff Duquette ]

[rexford]

"Shrapnel casing does shatter upon detonation of the base charge."

It's rather obvious that the casing would shatter upon detonation, or else the balls would not do their thing. The web site stated that the casing on early shrapnel was not designed to fragment.

U.S. cloverleaf diagrams for 75mm HE, a very potent round, show that with a 30' air burst and a 30 degree descent angle the fragment density is very low infront of the detonation. Most of the fragments are blown to the sides.

This suggests that casing fragments along the line of fire from 76.2mm shrapnel might be insignificant at 115m range when the round detonates at 15m.

[rexford]

The one thing about John Salt's analysis that keeps me going over the ideas is the concept that each ball has the same probability of being at any one spot in the ring.

From a simplistic view, balls on the left side of the shrapnel round at the time of detonation might have a higher chance of being on the left, and vice versa. And balls at the top of the round at detonation might have a higher probability of being at the top of the ring.

In other words;

If the powder charge detonation within the shrapnel round produces equal pressure on the bottom of the balls, balls on the left side would have a greater chance of going left and vice versa from internal pressure.

The fact that the balls spread out 10m to the left and right of the line of fire at 80m shows that there may be some pressure within the stream pushing balls away from the centerline.

This stuff is not my specialty (eating and gaining weight is), and the above is based on some fanciful impressions that occurred inbetween spoonfuls of Turkey Hill French Vanilla ice cream. Corrections and suggestions welcome and invited.

[tabpub]

Originally posted by rexford:

This stuff is not my specialty (eating and gaining weight is), and the above is based on some fanciful impressions that occurred inbetween spoonfuls of Turkey Hill French Vanilla ice cream. Corrections and suggestions welcome and invited.

Congratulations! When is the Redwolf cub due?

[tar]

The one thing about John Salt's analysis that keeps me going over the ideas is the concept that each ball has the same probability of being at any one spot in the ring.

That's not quite what is being computed. Instead, the computation is more along the lines of the probability of there being any ball at that particular spot in the ring. This is done by making some uniformity assumptions about the distribution, namely that it is symmetric about the axis of the shell's flight.

Simplifying a bit, one then takes the number of balls and divides them by the area to figure out how many one might expect to find in that area. This method looks at the chance of any ball being in that area, but it means any in the generic sense rather than in the sense of each ball. It is done this way so that one can analyze things without getting trapped in minutiae like having to compute the chance of each one (of 900!) being at a particular place in the beaten zone.

I hope this clarifies rather than muddies the ideas.

[MikeyD]

My one concern involves attempts to calculate the 'cone of dispersion' for the 7.62mm case-shot round. I've got a solid mental picture of an expanding cone of dispersion for cannister/shotgun rounds. The pellets exit the barrel and disperse. But if case-shot is actually a schrapnel round with the fuse set to 10 feet I have a mental picture of a water balloon bursting in mid-air, the dispersion would be up/down/back/forth from the burster explosion! Sure, momentum would carry the expanding cloud of fragments forward but I'd imagine the dispersion footprint would widen abruptly, not expand linearly like a shotgun round.

[ June 09, 2003, 12:49 PM: Message edited by: MikeyD ]

[flamingknives]

Flamingdoublepost

[ June 09, 2003, 02:17 PM: Message edited by: flamingknives ]

[flamingknives]

It kind of depends how big the bursting charge is as to how the balls disperse. Mauser are currently marketing a computerised shrapnel shell for their 30mm cannon, and that description has the bursting charge being rather small, just enough to separate the balls rather than explode.

The description of the 76.2mm shell in the german document uses the word 'sprengpunkt', which my dictionary tells me means 'break up point' as much as 'blast point'. I may well be wrong here, but it seems to describe a less energentic dispersal of the shrapnel.

Assumptions are 626 m/s muzzle velocity, an added 60 m/s for shrapnel powder charge (per John Kettler's figure, which may not be 100% correct but is a start), and balls act independently of one another with little influence on aerodynamics of other balls (simplifying assumption that is not technically true).

Stealing this info from an earlier rexford post, you can work out that even shrapnel acclerated directly back down the flight path are still going forwards at about 550m/s just in front of the muzzle

[MikeyD]

Still, I bet the 76mm field gunners were mighty happy to have that big gun shield between them and the bursting case-shot round! I notice in the drawings the small amount of explosive behind the balls, with what you might describe as an angled 'kick plate' that would push the pellets forward and out from the explosion. The gunner would just have to worry about a couple big pieces from the shell rear coming back at them.

[rexford]

Originally posted by tar:

</font><blockquote>quote:</font><hr /> The one thing about John Salt's analysis that keeps me going over the ideas is the concept that each ball has the same probability of being at any one spot in the ring.

That's not quite what is being computed. Instead, the computation is more along the lines of the probability of there being any ball at that particular spot in the ring. This is done by making some uniformity assumptions about the distribution, namely that it is symmetric about the axis of the shell's flight.

Simplifying a bit, one then takes the number of balls and divides them by the area to figure out how many one might expect to find in that area. This method looks at the chance of any ball being in that area, but it means any in the generic sense rather than in the sense of each ball. It is done this way so that one can analyze things without getting trapped in minutiae like having to compute the chance of each one (of 900!) being at a particular place in the beaten zone.

I hope this clarifies rather than muddies the ideas. </font>

[rexford]

"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.

[John Kettler]

Alas, this thread had tremendous momentum--until it was swallowed by a black hole!

Regards,

John Kettler

[tabpub]

Please, keep this thread alive!

Re-reading it over and over is the only cure for my insomnia! The doctors are all amazed at the results!

[John D Salt]

Originally posted by tabpub:

Please, keep this thread alive!

Re-reading it over and over is the only cure for my insomnia! The doctors are all amazed at the results!

What else is there to say?

Unless, of course, someone wants to point out how the canister model could be generalised to deal with airburst shrapnel by spreading the balls over an ellipse, and taking the target area of a man as the projection from the point of burst. But how does one model the zone of the fuze? As so often in life, stochastic simulation is the only sensible answer.

All the best,

John.

[Andreas]

Does anyone else think the last sentence by John sounded like the beginning of the explanation on how to play 'One song to the tune of another' on 'I'm sorry I haven't a clue'?

[Jeff Duquette]

Lorrin Said: “It's rather obvious that the casing would shatter upon detonation, or else the balls would not do their thing. The web site stated that the casing on early shrapnel was not designed to fragment.”

It depends upon the shell. It is also probably obvious that shrapnel shell came in several forms. I won’t delve into shrapnel employed in an AAA mode…still a popular form of ordnance with anti-aircraft gunners even during WWII.

Shrapnel balls were typically either packed in resin matrix or high explosive matrix. The former being the packing material of choice for the French and British; the later being the Germans choice du jour (and possibly the Russians\Soviets as evidenced by the amount of fragmentation within their particular brand of shrapnel shell). The Germans at least did count upon the HE packing for generation of casualty producing splinters from the bursting shell casing. This form of shrapnel projectile was used en masse by the Kaiser’s cannoneers.

Regarding fuses, and the not so subtle differences between shrapnel and canister, most of the shrapnel producing countries installed what is called a combination fuse in shrapnel shells. This appears to have been a late-WWI tweak that continued to be a standard feature during the post-WWI period. The combination fuse included both a time action element and a percussion action element. The time action fuse, if functioning properly and set properly, would give shrapnel its airburst capability. However the unreliability of the time action fuse was such that a back-up percussion fuse became a standard feature in shrapnel. The percussion fuse ensured detonation of the shrapnel shell upon impact with the ground (or tree top or other solid object). The percussion mechanism is designed primarily to insure action of the shrapnel in case of failure of the time mechanism.

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 long and short of it is that shrapnel isn't canister. At times folks in desperate straits used shrapnel in a pseudo-canister role...a wanna be canister projectile. But a single T-34 firing shrapnel isn't always gonna result in the mother of all big-assed 10-gauge shotguns. There is to much fuse action slop to say: "shrapnel is canister". Shrapnel fuse slop would result in a range of potential outcomes many of which would not resemble canister effect. The opposite ends of this spectrum being:

1) All works according to pland and the T-34's shrapnel shell acts like the mother of all big-assed shotguns or;

2) Shrapnel fuse slop results in shrapnel shell wizzing harmlessly by the intended infantry target at 600 m/s. It than explodes harmlessly 100-yards to the rear of the infantry target and sprays its pellets in the opposite direction as the intended target.

This is the not so subtle difference between simple canister and fused shrapnel.

Hopefully the above continues to help those amongst us that are suffering from bouts of sleep deprivation.

[ June 17, 2003, 08:27 PM: Message edited by: Jeff Duquette ]

[tabpub]

Actually, when the "canister" round first debuted, I was among the first to come out and say "WTF" is that! Now that it is being determined that it is a short fused shrapnel round, I feel mildly vindicated...and sleeppyy, so verrrry sleeepppyy... :cool:

[Jeff Duquette]

More medicine for insomnia...

I too brought this up back in the days of the DEMO. I chalk up 76mm canister to urban legends ala US Army 57mm APDS and German Stug-III’s firing canister. From a gaming research standpoint, one has to wonder how Soviet 45mm and 57mm canister got lost in the mix, yet non-existent 76mm canister is quite prevalent and can even be employed by field guns outfitted with muzzle breaks. Information on both the Soviet 45mm and 57mm canister rounds is fairly abundant (like US Army 37mm canister).

On the other hand tidbits like US Army 57mm APDS and German Stug canister can usually be traced back in time to one reference. Those of us anxious to find corroborating evidence, or additional source references would be hard-pressed to produce the like for either of these forms of ammunition. The use of a particular projectile should be well detailed\documented within standard army ordnance guides, army ammunition manuals, gunnery manuals, and\or army ranges tables. In theory such information should be easy to unearth, particuarly if the piece of ordnance in question was in common use. If the Army of interest wasn’t training its soldiers the use of a particular piece of ammunition, and that same army was not producing literature on the employment of specific forms of ammunition it’s a pretty good bet that either the projectile never existed, or the projectile was some sort of obscure experimental model that was never released to the army.

For example 75mmL24 canister; the official H.Dv.Merkblatt for this weapon has sectionals of numerous ammunition types employed by this weapon including some rather odd forms of ammunition that I suspect the vast majority of us have never heard of before. However there isn’t anything in the way of a canister round.

This question of the existence of a 75mmL24 canister round was raised earlier in this thread, and a URL was produced in the way of corroborating evidence for the existence of a Stug canister round. To digress a bit, the original legend of the Stug and early Panzer-IV’s canister round seems to be brought to us by a brief, fine print footnote, hidden in the tail ends of two books on German tanks. Both were written by F.M. von Senger und Etterlin and include: “German Tanks of WWII” & “Die Kampfpanzer von 1916-1966”. Doubtless the von Senger reference to canister was perpetuated by inclusion of Stug canister in several old mass consumption board wargames that also relied upon von Senger as a primary source of information. Thus the legend becomes accepted "fact". (I lost interest in AH's Squad Leader after Cross of Iron. Did any of the Advanced Squad Leader iterations include 75mmL24 canister?)

Fast forward to 2003 and we find a Web site that seems to independently corroborate the von Senger fine print footnote regarding Stugs and early Panzer-IV's using canister. However close examination of the Panzer-IV Universe web site reveals that the Author of this web site is relying upon – that’s right, you guessed it -- F. M. von Senger und Etterlin, “Die Kampfpanzer von 1916-1966”.

You will find several other references of interest on this web page to include the US WAR Department’s excellent TO 39B-1A-10; “German Explosive Ordnance”. Like the German Army’s Merkblatt, this extensive manual on German projectiles, ranging in caliber from 20mm to 150mm, shows no evidence of a 75mmL24 canister round.

My question is can anyone produce a photograph, an official design drawing, schusstafeln, or an official Heer gunnery manual that details use of canister by the 75mmL24?

[ June 17, 2003, 08:17 PM: Message edited by: Jeff Duquette ]

[rexford]

Originally posted by Jeff Duquette:

More medicine for insomnia...

I too brought this up back in the days of the DEMO. I chalk up 76mm canister to urban legends ala US Army 57mm APDS and German Stug-III?s firing canister. From a gaming research standpoint, one has to wonder how Soviet 45mm and 57mm canister got lost in the mix, yet non-existent 76mm canister is quite prevalent and can even be employed by field guns outfitted with muzzle breaks. Information on both the Soviet 45mm and 57mm canister rounds is fairly abundant (like US Army 37mm canister).

On the other hand tidbits like US Army 57mm APDS and German Stug canister can usually be traced back in time to one reference. Those of us anxious to find corroborating evidence, or additional source references would be hard-pressed to produce the like for either of these forms of ammunition.

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.

[Jeff Duquette]

Lorrin:

Firstly, Advanced Squad Leader is hardly a primary source of historical information. A great game on par with CMBO & CMBB, but ASL is hardly a research tool.

Secondly, your passion is admirable, but is unfortunately misplaced on this mater. This conviction of yours aside for moment, there has been no real evidence that has come to light on this or any other of your forums that the US ever produced 57mm APDS – aside from several vague GI war stories. But while we are on the topic perhaps you can post the entire text of the report from the 90th ID and indicate the exact source. I actually possess several manuals containing photo copies of 90th ID Action Reports from Normandy as well as the breakout period.

I am also curious as to how you would explain the lack of any 57mm APDS evidence within all of the following references:

1) The US Army’s 57mm Antitank gun firing tables.

2) The US War Departments 57mm AT gunnery manual (FM 23-75).

3) The War Departments WWII Standard Catalogue of US Army Ordnance.

4) War Department TM 9-1900 Ammunition

5) War Department TM 9-303 57mm Gun M1 and Gun Carriages M1 through M1A3.

6) TM 9-1907 Ballistic Data, Performance of Ammunition (both the 1944 and 1948 editions).

Even the voluminous 1946 BRL catalogue of US Army projectile ballistic testing data employed during the war lacks any evidence of a 57mm APDS round. Yet this same extensive catalogue details the capabilities of the ever elusive -- extremely limited production run – T16 57mm HE round (that’s a “T” …not an “M”). There isn’t even a “T” version of a 57mm APDS round on the books.

If the US Army 57mm APDS had indeed ever been produced surely it would be rather simple to uncover Army generated technical data on the projectile. What was the BRL established projectile nose length?...what did BRL use for a form factor?...what reference drag function was employed...what was the drag coefficient? The Army, by this time in its history, wasn’t in the habit of producing projectiles without some form of ballistic testing. Where’s the beef? Perhaps a little less ice cream indulgence and a bit more research would be in order.

If you would be kind enough to produce a US War Department firing table, training manual or BRL generated ballistic data that details anything associated with US Army produced 57mm APDS, I will be more than happy to admit that I am in error on this subject.

[ June 18, 2003, 02:08 AM: Message edited by: Jeff Duquette ]

[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.

[rexford]

Originally posted by Jeff Duquette:

Lorrin:

Firstly, Advanced Squad Leader is hardly a primary source of historical information. A great game on par with CMBO & CMBB, but ASL is hardly a research tool.

Secondly, your passion is admirable, but is unfortunately misplaced on this mater. This conviction of yours aside for moment, there has been no real evidence that has come to light on this or any other of your forums that the US ever produced 57mm APDS ? aside from several vague GI war stories. But while we are on the topic perhaps you can post the entire text of the report from the 90th ID and indicate the exact source. I actually possess several manuals containing photo copies of 90th ID Action Reports from Normandy as well as the breakout period.

I am also curious as to how you would explain the lack of any 57mm APDS evidence within all of the following references:

1) The US Army?s 57mm Antitank gun firing tables.

2) The US War Departments 57mm AT gunnery manual (FM 23-75).

3) The War Departments WWII Standard Catalogue of US Army Ordnance.

4) War Department TM 9-1900 Ammunition

5) War Department TM 9-303 57mm Gun M1 and Gun Carriages M1 through M1A3.

6) TM 9-1907 Ballistic Data, Performance of Ammunition (both the 1944 and 1948 editions).

Even the voluminous 1946 BRL catalogue of US Army projectile ballistic testing data employed during the war lacks any evidence of a 57mm APDS round. Yet this same extensive catalogue details the capabilities of the ever elusive -- extremely limited production run ? T16 57mm HE round (that?s a ?T? ?not an ?M?). There isn?t even a ?T? version of a 57mm APDS round on the books.

If the US Army 57mm APDS had indeed ever been produced surely it would be rather simple to uncover Army generated technical data on the projectile. What was the BRL established projectile nose length?...what did BRL use for a form factor?...what reference drag function was employed...what was the drag coefficient? The Army, by this time in its history, wasn?t in the habit of producing projectiles without some form of ballistic testing. Where?s the beef? Perhaps a little less ice cream indulgence and a bit more research would be in order.

If you would be kind enough to produce a US War Department firing table, training manual or BRL generated ballistic data that details anything associated with US Army produced 57mm APDS, I will be more than happy to admit that I am in error on this subject.

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 ]