Max Hit Probability

[rexford]

1m vertical dispersion at 800m for 50% of 75L48 HE is doppelte streung dispersion. Actual vertical dispersion at 800m is 0.45m above aim center and 0.45m below, double dispersion used in analysis is 1.0m above or below.

This data is based on actual German firing tests conducted at a few ranges between 0m and 3000m, with a curve drawn between the data points.

It is real data taken from a German ballistic table, we have these tables for APC, APCBC, HEAT and HE rounds.

The overriding point is that if the vertical dispersion for L24 and L70 German 75mm HE was 0.3m, the L24 still is more accurate than L70 in terms of landing rounds close enough to cause losses. The analyse's at the bottom of page 7 in this thread show this conclusively, and since those studies used 450 m/s for L24 HE and it could be as low as 385 m/s, advantage over L70 HE is even greater.

Vertical dispersion at 400m would be about half of 800m figure, although descent angles would also be about half, so beaten zone at 400m would be slightly smaller than 800m.

Panther HE takes 0.6 seconds to 400m, PzKpfw IIIN 75 HE takes 1.1 seconds, so IIIN HE trajectory will still be curvier. Panther 75 HE descent angle at 400m is still going to be larger than PzKpfw IIIN HE at 400m, difference between the two will be smaller than at 800m.

[rexford]

In my last post, one correction:

Panther HE descent angle at 400m will still be smaller than PzKpfw IIIN 75L24 HE.

[:USERNAME:]

Heres the data from the panzer IV website. I believe that Rex claims that the website showed that there is two HE velocitys shown there. I could not find that but found the following interesting information:

Muzzle Velocity (m./sec.)

L/24 w/ Pzgr. (Kw. K. 38) {APC?}

385

L/24 w/ Sprgr. Kw. K. (34) {HE}

420

L/43 w/ Pzgr. 39 Kw. K. 40 {APCBC}

740

L/43 w/ Pzgr. 40 {AP40}

930

L/43 w/ Sprgr. Patr. Kw. K. (34) {HE}

550

L/48 w/ Pzgr. 39 Kw. K. 40 {APCBC}

750

L/48 w/ Pzgr. 40 {AP40}

930

L/48 w/ Sprgr. Kw. K. (34) {HE}

550

I added the {info} for clarification.

Maybe Rex is confused or I missed something. But I could not find two HE velocitys for the 75L24 guns HE shells (or other 75mm class of weapons). I hope BTS is as interested in this as I am. The KWK (34) is the designation for the heavy payload HE shell. I hope others here can post some more info about it.

Lewis

[:USERNAME:]

Also from my "picture book" (I'll give that jerk credit..that WAS funny):

"In addition, the assault gun crews could also use the Explosive shell 34. these shells were made of pressed or cast steel. They had an impact igniter with adjustable delay (0.15 secs) which allowed the shot effect on the target to be set optimally. For example, when firing ricochet shots, the igniter was set for delay. The shot , landing flat on the ground, bounced off and exploded only when the igniter setting was reached. With ricochet firing, great splinter effect could be achieved against living targets not covered from above."

Also on the HE:

..7.5 cm Explosive shell 34 of the 7,5 cm Assault gun 40..the shell weighed 5.74 Kg and contained 0.68 kg explosive. The splinter effect extended up to 15 meters to the sides and seven meters to the front."

I wonder if there could be a typo somewhere. Since the website mentions 0.86 and here it states 0.68. I really think 0.86 is ALOT for a 75mm weapon that would weigh 5.74 Kg.

I dont know if the author is speaking of a ground burst for the HE shell. It would seem so. An airbust would be something to be further than 7 meters away from.

Now back to looking at my pictures ...la ..la.ladeeda..

Lewis

PS To All you asian types. Happy new year.

[Jeff Duquette]

Hmmm…yes…well this discussion on the weights and velocities of the 75mm is certainly titillating. I was wondering if we could return to a discussion on accuracy.

USERNAME can you tie all these weights and velocities back into the discussion so we can all be on the same sheet of notes…so to speak. You seem like an intelligent enough fellow, and this stuff can be fun to talk about. It’s our hobby, and if we weren’t having fun with it…well than it wouldn’t be a hobby…it would be work. We don’t have to act like we’re all a bunch of sweaty professional wrestlers threatening to beat each other over the noggins if we miss place a decimal. Can’t we all just get along

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

A supplemental post to what Rexford is talking about with dispersion. The following is actually discussing horizontal dispersion as applicable to artillery fire, however this info is equally valid to vertical dispersion…simply assume line of fire would be perpendicular to figures 3-9 and 3-10 (i.e. in and out of the page). In addition, horizontal dispersion tends to form a relatively elliptical shot pattern…very long and narrow along the line of fire (the length of course being very dependent upon angle of decent). High velocity fire, and its corresponding vertical dispersion tends to be much more symmetrical (more circular) around the mean impact point. The size of a particular dispersion pattern for a given munition at a given range would typically be measured during test firing. For vertical dispersion: Hohe (or high spread\height) and Breite (or lateral spread). For horizontal dispersion (I don’t know the German terms) you’re looking at range probable error (length) and deflection probable error (width).

For those that know this ****…sorry for wasting your time. For those that are a little vague on the wheres and whys of some of Rexford’s information\terminology hopefully the following will help.

From: Chapter 3, FM 6-40 FIELD ARTILLERY MANUAL CANNON GUNNERY

The distribution of bursts (dispersion pattern) in a given sample of rounds is roughly elliptical (Figure 3-9) in relation to the line of fire.

A rectangle constructed around the dispersion area (excluding any erratic rounds) is called the dispersion rectangle, or 100 percent rectangle. (See Figure 3-10.)

3-6. Mean Point of Impact

For any large number of rounds fired, the average (or mean) location of impact can be determined by drawing a diagram of the pattern of bursts as they appear on the ground. A line drawn perpendicular to the line of fire can be used to divide the sample rounds into two equal groups. Therefore, half of the rounds will be over this line when considered in relation to the weapon. The other half of the rounds will be short of this line in relation to the weapon. This dividing line represents the mean range of the sample and is called the mean range line. A second line can be drawn parallel to the line of fire, again dividing the sample into two equal groups. Half of the rounds will be to the right of this line, and half will be to the left. This line represents the mean deflection of the sample and is called the mean deflection line. (See Figure 3-9.) The intersection of the two lines is the mean point of impact (MPI). (See Figure 3-10.)

3-7. Probable Error

Probable error is nothing more than an error that is exceeded as often as it is not exceeded. For example, in Figure 3-11, consider only those rounds that have impacted over the mean range line (line AB). These rounds all manifest errors in range, since they all impacted over the mean range line. Some of the rounds are more in error than others. At a point beyond the MPI, a second line can be drawn perpendicular to the line of fire to divide the "ovens" into two equal groups (line CD, Figure 3-11). When the distance from the MPI to line CD is used as a measure of probable error, it is obvious that half of the overs show greater magnitude of error than the other half. This distance is one probable error in range. The range probability curve expresses the following:

a. In a large number of samples, errors in excess and errors in deficiency are equally frequent (probable) as shown by the symmetry of the curve.

b. The errors are not uniformly distributed. Small errors occur more frequently than large errors as shown by the greater number of occurrences near the mean point of impact.

3-8. Dispersion Zones

If the dispersion rectangle is divided evenly into eight zones in range with the value for 1 probable error in range (PER) used as the unit of measure, the percentage of rounds impacting within each zone is as indicated in Figure 3-12. The percentage of rounds impacting within each zone has been determined through experimentation. By definition of probable error, 50 percent of all rounds will impact within 1 probable error in range or deflection of the mean point of impact (25 percent over and 25 percent short or 25 percent left and 25 percent right).

[This message has been edited by Jeff Duquette (edited 01-24-2001).]

[rexford]

Oops! Made a mistake. 75L24 HE fired at 420 m/s.

Sent in post after dental appointment and misread sheet.

[:USERNAME:]

Originally posted by Jeff Duquette:

Hmmm…yes…well this discussion on the weights and velocities of the 75mm is certainly titillating. I was wondering if we could return to a discussion on accuracy.

USERNAME can you tie all these weights and velocities back into the discussion so we can all be on the same sheet of notes…so to speak. You seem like an intelligent enough fellow, and this stuff can be fun to talk about. It’s our hobby, and if we weren’t having fun with it…well than it wouldn’t be a hobby…it would be work. We don’t have to act like we’re all a bunch of sweaty professional wrestlers threatening to beat each other over the noggins if we miss place a decimal. Can’t we all just get along

[This message has been edited by Jeff Duquette (edited 01-24-2001).]

Hmmmmm Jeff

I believe BTS expressed an interest in this. Just excuse me if you can. The weights and velocitys have a DIRECT impact on the discussion.

Spare me the political rhetoric. I want an accurate game and I believe there is a moderating prescence here. Alot of what Rex is putting forth is BASED on this data. So let the moderating people moderate.

I think he (Rex) has already modified his stance and I am beggining to understand what his point is. He unfortunately has used linear thinking wrong in my opinion.

As for the hobby. I really think this is part of it! Some people get off on Mods (Nothing wrong with that) and some people get off on detail in simulation. They like dat and such.

Now, I dont have your posting illustration abilitys. You have me at a disadvantage. I express myself with words. I also have to be careful of my words because of people running out and snipping at my heels and then buggering off. I dont react well to that.

No problem.

I can deal. But I am not a modertator and neither are you. I am going to express my point. Believe it or not its actually for everyones benefit.

You enjoy the game at a certain level and so will I. I want the most accurate simulation going for BTS and the hobby.

Lewis

[Jeff Duquette]

Great...lets hear your point already.

[:USERNAME:]

I have many points:

1. Rex is incorrect in his "vertical dispersion" theorys.

2. There seems to be an interesting German 75mm HE mystery going on

3. Fighting on a perfectly flat plain is perfect for skipping HE rounds

4. Artillery and direct fire shouldnt be confused.

And some others but which one would you like me to address first?

Lewis

[PzKpfw 1]

Originally posted by :USERNAME::

I have many points:

And some others but which one would you like me to address first?

Lewis

All of them in a detailed fashion.

Regards, John Waters

------------------

"We've got the finest tanks in the world. We just love to see the

German Royal Tiger come up on the field".

Lt.Gen. George S. Patton, Jr. February 1945.

[ASL Veteran]

Originally posted by :USERNAME::

I have many points:

1. Rex is incorrect in his "vertical dispersion" theorys.

2. There seems to be an interesting German 75mm HE mystery going on

3. Fighting on a perfectly flat plain is perfect for skipping HE rounds

4. Artillery and direct fire shouldnt be confused.

And some others but which one would you like me to address first?

Lewis

I don't believe that dispersion is Rexford's theory - dispersion is something that is already established and recognized in various field manuals and range tests. Could your disagreement be in the way that Rexford is applying dispersion? If so, in what way is Rexford misapplying dispersion to his calculations?

[:USERNAME:]

Originally posted by ASL Veteran:

I don't believe that dispersion is Rexford's theory - dispersion is something that is already established and recognized in various field manuals and range tests. Could your disagreement be in the way that Rexford is applying dispersion? If so, in what way is Rexford misapplying dispersion to his calculations?

I disagree with the way he is applying it.

Yes I agree with the fig 3-9 in jeffs post above. It shows the distribution of rounds from a birds eye view.

Now vertical dispersion is what? Is it the + or - height differential at the top of the flight of the shell? How is it measured? Where is it measured? Is rex positive he understands the documents? Does he speak german?

Is it an angular error that can be tracked back to the gun like Ben calculated? If it is an angular error, then it would manifest itself in shells going further or shorter? Is the angular error constant? That is, if the range is decreased, does the error decrease? linearly?

Does the Panther gun then start doing better at longer ranges? Does it do better at shorter ranges? Wouldnt a shorter barreled weapon have a greater angular error?

I also disagree with Rex's equating infantry as point targets. A 12 man rifle squad using 5 meter intervals is a large target covering alot of space. I would model it as a 4 by 3 rectangle giving 20 meter by 15 meter. The casualty zone for a 75mm shell is not that large and would be lucky to take out 1 or 2 guys.

In reality, such flat terrain is rare. It would be somewhat difficult to guage whether your rounds were short or long in any case. A height advantage would help and the panther has a built in height advantage. If a panther can lob HE accurately enough to hit a tank at 2000 meters then it cant be that much harder to hit a 300 squre meter target.

When i get the chance i will do the math. I would like for rex to respond and define what vertical dispersion is and how its measured.

Lewis

[rexford]

Lewis,

Your comments about my posts have already been responded to.

1. Vertical dispersion is applied about the mean trajectory calculated using just gravity and initial elevation angle.

If the mean trajectory height is 1m above the ground and 50% of the dispersion will be within 0.5m, then 50% of the shots will be between 0.5m and 1.5m above the ground.

My friends speak fluent German, some of their fathers were test pilots and the like during the war, and everything on the German ballistic tables has been thoroughly translated and made sense of.

2. Ground point targets occur when a target is a point on the ground, which occurs in the example you referred to.

3. The superiority of 75L24 HE over 75L70 HE is based on the attempt to drop an HE near the middle of a point target on the ground. Would ricochet fire always be used instead of aimed fire at point targets?

No.

Terrain between target and gun may be rough.

Looked at another way, if 75L24 HE lands closer to point that is aimed at, ricochet fire with 75L24 might be more accurate than 75L70 HE.

4. We are really thankful for some of the info you have provided.

5. Unless you back-up your assertions with analysis, and stop playing games with "how do you define dispersion and then I'll correct you", your posts lack any validity and appear to be nothing more than attempts to discredit our posts by creating doubt.

Back up your assertions with some hard math, like we did.

If you cannot understand what a "ground point target" is, then further discussion is useless.

Bye.

[Matthew_Ridgeway]

I'm sorry Steve and BTS for what is about to follow, but this simply boggles the mind...I can't restrain myself.

Are you for real UsER? This isn't some theory that Rexfred came up with on the back of an envelope. This is the way shot dispersion is measured. As the rather astute ASL_Squadleader has already put it: "I don't believe that dispersion is Rexford's theory - dispersion is something that is already established and recognized in various field manuals and range tests."

How do you measure vertical dispersion you ask? You strap a weapon down to a frickin test frame that's bolted down on a frickin' concrete pad and, you measure the frickin' range to a frickin' upright target. You adjust your frickin' sights to that exact frickin' range, than you shoot a bunch of frickin' holes in the frickin' upright target. The shot pattern around the frickin' aim point is your frickin' dispersion pattern. A bunch of frickin' shots will be clustered around the frickin' aim point. Measure how big the frickin' scatter pattern is, both in the frickin' X direction (Breite) and frickin' Y direction (Höhe). The area that includes 50% of your frickin' shots is the frickin' 50% dispersion frickin zone at range "such and such". Than you do the whole freckin' thing over again, except the frickin' upright frickin' target is now at 100m further away, or whatever your test frickin' range increment happens to be.

And there is no mystery about the German 75mm: weights, velocities, or trajectories. The only mystery on this thread is your total lack of understanding as to what is even being discussed here.

[:USERNAME:]

Originally posted by Matthew_Ridgeway:

How do you measure vertical dispersion you ask? You strap a weapon down to a frickin test frame that's bolted down on a frickin' concrete pad and, you measure the frickin' range to a frickin' upright target. You adjust your frickin' sights to that exact frickin' range, than you shoot a bunch of frickin' holes in the frickin' upright target. The shot pattern around the frickin' aim point is your frickin' dispersion pattern. A bunch of frickin' shots will be clustered around the frickin' aim point. Measure how big the frickin' scatter pattern is, both in the frickin' X direction (Breite) and frickin' Y direction (Höhe). The area that includes 50% of your frickin' shots is the frickin' 50% dispersion frickin zone at range "such and such". Than you do the whole freckin' thing over again, except the frickin' upright frickin' target is now at 100m further away, or whatever your test frickin' range increment happens to be.

And there is no mystery about the German 75mm: weights, velocities, or trajectories. The only mystery on this thread is your total lack of understanding as to what is even being discussed here.

You know what the funny part is? He doesnt agree with you!!!!!!!!

"1. Vertical dispersion is applied about the mean trajectory calculated using just gravity and initial elevation angle.

If the mean trajectory height is 1m above the ground and 50% of the dispersion will be within 0.5m, then 50% of the shots will be between 0.5m and 1.5m above the ground."

Seems he is describing an observation made from the side as the shell goes by ( a Z axis variance) and you are describing what Jeff posted in those figures above!

You just made my frickin' day!!!!!! How do you feel?

Lewis

[Matthew_Ridgeway]

you are clueless.

[:USERNAME:]

Originally posted by rexford:

Lewis,

Your comments about my posts have already been responded to.

1. Vertical dispersion is applied about the mean trajectory calculated using just gravity and initial elevation angle.

If the mean trajectory height is 1m above the ground and 50% of the dispersion will be within 0.5m, then 50% of the shots will be between 0.5m and 1.5m above the ground.

2. Ground point targets occur when a target is a point on the ground, which occurs in the example you referred to.

To whom it may concern

I am confused. You say "we" alot but you also say "responded to my posts" also. Who am I talking to?

Anyway. I need one piece of clarification. Is the following a true statement:

If the mean trajectory height is 1m above the ground (assuming a zero height starting point lets say) and 50% of the dispersion will be within 0.5m, then 50% of the shots will be between 0.5m and 1.5m (these are the 50 percent boundary "mean trajectory heights")above the ground.

I just need confirmation on that to calculate.

Now. Ground point targets may be semantics but do you agree that a squad spread out like I described is a big ground point target? 20 times 15 gives 300 square meters. A large tank is perhaps 3 by 5 meters. Thats 15 square meters. The 300 square meter target is about 20 times the size. Its not needed to land the shell directly in the middle. In fact the target is larger because the outside area should be counted also. A round landing 10-15 meters on the side could clip one of the "points" in the large point target.

Anyway. Hope to hear from you on the clarification. looking forward to the math.

Buh-bye y'all

Lewis

[Jeff Duquette]

I came across this web site yesterday (when I should have been diligently working). The web site is basically a unit history of the US ARMY 635th TD battalion in ETO 44-45. Fairly well detailed as web site unit histories go. Unit was equipped with the towed 3". From the read it appeared that the 635th saw a great deal of time at the front, including: Normandy, Lorraine, Hurtgen, Siegfried line, B of B, and finally into Germany. What struck me was the limited numbers of engagements the unit had with panzers. The history does contain a fair number of tales about getting shelled and suffering casualties from HE. Anyway I went through the whole ****-oh-ree, and pulled out those AAR's, which detailed both range of engagements and numbers of rounds fired. Impressive range\accuracy results for these 3" guns.

THE 635th TANK DESTROYER BATTALION IN EUROPE IN WORLD WAR II

by Carl Condon

http://skyways.lib.ks.us/museums/kng/635TDB.html

Camouflaged enemy tank spotted in Company B area obviously bogged down in swamp terrain, 57mm gun unable to hit tank. On order Sergeant Cumming's gun (sic. Cummings sections was equipped with the 3" gun) fired 9 rounds and had six direct hits-distance 2500 yards. Battalion surgeon advised Schuetz and Maderis, Severely Wounded In Action to Died Of Wounds.

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

Ray Klein, Company B, tells this story-On June 22, 1944, Colonel Taylor of the 18*

Regiment, 1st Infantry Division told me that a German tank was firing into the Battalion area. He said to locate the tank and stop the firing. The 2nd Lieutenant in charge of their platoon of 57mm anti-tank guns and I moved one of our 3rd platoon 635th 3" guns into a spot where we had a clear shot. The German tank was spotted camoflouged on a small trail of a forward slope. I had a BC scope and estimated the distance at 2500 yards. He and I had a wager on the distance. We hit the tank with our 1st round of APC. A couple of the crew bailed out, so we fired some HE around it.

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

A Company reported-lst platoon on Oct 10th between 1230 and 1300 hours fired 22 rounds of APC and 6 rounds of HE at pillbox in front of their position. Pillbox neutralized. All direct hits-range 1700 yards. Fire also directed to aid confusion made by feint attack by Group in aid of southern drive by 9th Infantry Division.

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

Company A reported- At 1415 hours Sergeant Carroll's gun section, 4th platoon, in

position approximately 2800 yards southwest of Esch, Germany, fired at an enemy tank and CP house and observation point in Esch. Direct hits were observed on both tank and house obviously neutralizing the object as no additional fire was received from that point. Number of casualties unknown. (Upon arrival in Esch, Battalion Commander checked position and found that tank sustained direct hit in right bogie, immobilizing the tank which was definitely identified as a Tiger VI. Crew unable moved out, placed a charge of explosives inside tank, destroying it for further use. 4th platoon credited with a Tiger VI.

The Proverbial Tiger Tank that lurked around every bush in France and Germany.

[rexford]

Lewis,

A ground point target is fired at by aiming at a specific point on the ground. Ten men spread over an area requires the gun to aim at a specific ground point. This is so simple. One aims at a single point. Has to aim somewhere.

And my trajectory dispersion definition is correct.

My previous analysis showed that 75L70 HE will spread over a greater area than 75L24 HE, so if a squad covers a specific area and fire is aimed at middle of group, 75L24 HE has greater chance to land HE close enough to "area" to impact squad.

But an "area" target is still a ground point target because the gun is aiming at a single point on the ground.

Awaiting your ballistic analysis. Presented mine and noticed that no substantive comments were made. In fact, no response at all to the math.

On another matter, 88L56 HE fired at 810 m/s but vertical dispersion very small, so beaten zone not as large as velocity would imply.

I have now repeated the definition of ground point target at least 20 times, and it appears that you still don't understand how I am using the term. Please reread my previous posts and instead of attacking the explanation, try to let it sink in.

[rexford]

My explanation of dispersion agrees 100% with Ridgeway post. Dispersion is measured about mean impact point, which is the mean trajectory height.

The 'Natter Gap thread is 100,000 times more interesting than this unending and unfruitful attempt to communicate, and my wife found the 'Natter Gap posts funny, too. The little yellow moving objects shocked her a bit, though, which was good to see.

[Jeff Duquette]

I almost feel out of my chair reading the "Natter Gap" post. Too funny.

[:USERNAME:]

Originally posted by rexford:

Dispersion is measured about mean impact point, which is the mean trajectory height.

Rex et all

I keep trying to get you to be clear and you absolutely refuse to respond. The above sentance is just more of your indefite style of expression. I hope you dont take this wrong but your english isnt getting it.

What does the fact that you have to point your gun somewhere have to do with a target being an area target? Its the target thats the area target. Do you expect a gunner to close his eyes? You think the center of the mass of men is discernable under this wacky scenario you have made a point about? All the gunner would be able to see is the mass of men. He would not have a depth perception of the mass. The target is bigger than the effects of a ground burst from a 75mm HE. Thats what makes it such a juicy area target.

I wonder if maybe you can post the data somewhere. I just see here that you cant read data off the website I posted and you are really bewildering me with your psuedo-math.

Rex and the rest of "we". I really hope BTS pays attention to this thread and judges any "data" or theorys you post in the future on it.

Ive had enough of you (all).

[rexford]

Lewis,

Maybe your reading isn't getting it.

Do you have any substantive response to offer regarding the trajectory analysis on Page 7 that shows that 75L24 HE is better at placing rounds near the target point than 75L70 HE?

I presented a mathematical analysis with all the things you continously and non-stop asked for, descent angles, dispersion, flight times, etc., and you didn't say one word about the work. Just switched to another issue to hammer on.

Soldiers over an area are still a ground point target because the round is aimed at one point. See previous posts for definitions ad nauseum.

[LuckyStrike]

Lewis,

In order to kill men standing (or lying or whatever) on the ground, a shell fired at them must impact a POINT ON THE GROUND, so that the shell may explode. Therefore, one aims the shell AT THIS GROUND POINT TARGET, not at the men. Of course one's GOAL is to kill the men, but one must LAND the shell somewhere to do that.

How much more simple can it get? If you do not agree with the above, please tell us what exactly DO you aim a shell at aside from the ground (in the case of men in, say, an open field) so that it might be caused to explode? How do you suppose HE shells function?

[This message has been edited by LuckyStrike (edited 01-26-2001).]

[ASL Veteran]

I believe that the problem with the way Lewis is tackling this issue is that he is using 'area target' and 'point target' using a strict definition of each - which he sticks by to the point of ridiculousness. 'Point target' to Lewis is a bunker or a tank, 'Area target' is an infantry squad since it takes up a wide area if they are all dispersed at 5 meter intervals. Strictly adhering to these definitions, Rexford's description of a squad being fired upon as a 'point target' comes out as nonsense because a squad isn't a point target - it is an area target. Lewis can't (or is unwilling to) get past this point, so all the calculations that Rexford has made about trajectory and accuracy become nonsense since - according to Lewis - Rexford can't even define the target correctly. Of course, since Rexford's analysis deals with whether a target is a vertical target or a horizontal target and that the definition Lewis is using is irrelevant to Rexford's mathematics, they can't communicate effectively with each other. However, this is not the first 'issue' that Lewis got hung up on. There were other issues as well - equally ridiculous - and I am coming to the conclusion that Lewis is arguing for the sake of arguing and he probably enjoys all the attention that he is getting from someone who obviously has a great deal of knowledge on the subject. Lewis may feel that he is raising valid objections and important concerns about the data Rexford is presenting - unfortunately these objections and concerns come across as something other than important.

I have some interesting (to me anyway) data about Soviet velocities and shell weights which I may share later on if it is of interest. The Germans seem (to me anyway) to have made a conscious decision to make HE shells lighter and slower than their AP cousins from the same gun, but the Soviets do not seem to have shared that design philosophy. Sometimes their HE is the same velocity but heavier, and sometimes even heavier and faster. In fact, their HE weights and velocities are all over the map (possibly in both weights and velocities and perhaps in where they land too).