rexford
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Posts posted by rexford
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<BLOCKQUOTE>quote:</font><HR>Originally posted by :USERNAME::
I am going to do an experiment. I am going to shoot at paper vertical targets with a high velocity rifle and then I am going to turn the paper targets 90 degrees so they are flat and try to slice them with the same rifle. then I am going to chuck rocks skyward and when one comes crashing through the paper, I will prove rex right.
Then I will prove that 88L56 Tiger I tank guns arent good anti-aircraft weapons.
lewis<HR></BLOCKQUOTE>
Sir,
We are putting forth data that is supported by WW II German ballistic analysis,and our own review. Previous discussion should provide enough for you to understand the concept.
One additional note. At 800m, German data predicts that 50% of 75mm L48 HE will fall within a 61m long distance when range estimation against a ground target is exact. (50% will be more than 30m away from target ground point). This is at 550 m/s muzzle velocity.
88L56 HE at 810 m/s has a much larger ground dispersal.
Descent angles and dispersion for WW II Tank guns at 800m does result in large "errors". We used 800m because 750m data was not available.
We can't argue with these figures, and would welcome analysis that shows them to be incorrect.
(note, BTS fixed the quoting above. Rexford, you need to end the "quote" using "/quote" in brackets)
[This message has been edited by Big Time Software (edited 01-21-2001).]
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Thanks to Jeff Duquette for the excellent graohic that shows how low speed HE can be more accurate than higher velocity against ground point targets.
That makes Sherman 75 even more lethal compared to 76, slower velocity/mo' accuracy against ground point targets and more TNT, mo' pieces of shrapnel and mo' velocity on the pieces so they go through more and penetrate deeper. It ain't the total weight of shrapnel, it's the fragment total and velocity. A 155mm shell that breaks into two pieces is less of a danger than a 75mm that busts into 500!
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Tanks carrying mortars? Didn't some do this?
The question is valid though easily answered.
Mortars are good against "ground targets" but what about bunker openings, and buildings, and walls, and any number of vertical targets.
We're searching for HE weight in 75L24 and 75L70 HE, and will shortly have answer. Based on what I remember, 75L24 had more TNT than higher velocity HE from other German 75mm guns. Based on what appears to be the fact, higher velocity HE needs thicker walls than lower muzzle speed, so less TNT. This seems to be general rule.
Exceptions to rule may exist. An earlier post stated that miniscule HE shell fired by 17 pounder was beefed up with TNT by lowering the muzzle velocity. Consistent with general rule.
Everything in my posts is thought out and checked against multiple sources, has been reviewed with other members of the group and can be supported if someone wishes to ask for more back-up. Sometimes the statements are a bit short and sound simplistic, but the back-up is there.
Just ask if you are interested, and I'll provide whatever is needed. We don't know everything but what we state has usually been subjected to all sorts of review over the last 20 years. We're always cross-checking our stuff when something new pops up.
I work with Robert Livingston, and we were one of the first, if not the first, to identify the specific manner in which slope effects for steel projectiles are a function of T/D, that U.S. armor was flawed prior to 10/43, that the Panther glacis was flawed alot (but not always, and the front nose was hardly ever bad), we defined shatter gap in terms of specific factors, defined just how better U.S. 75mm HE is than 76mm HE in terms of casualty potential (it's not the total weight of shrapnel, it's the number of pieces and their velocity), etc.
I do the math, mostly statistical studies and curves of best fit, and ballistic/trajectory stuff. When our armor booklet comes out it will be the ultimate in compiled consistent data.
Sound like knee jerk reactions and fuzzy logick?
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Please note that I compared U.S. 76 HE to 75 HE, and spoke in general terms, did not specifically address German 75L70 and 75L24.
Knee jerk reaction, gross oversimplification?
Can't see any from this angle.
We will try to verify that 75L24 HE was not more potent than 75L70. Any one have any data on this?
If 10% max on Nashorn hit probability at 2000m is true, this should be looked at first.
My system uses range estimation error spread and applies to trajectory, with dispersion, and computes hit probability. If average error is 25%, o% errors occur and 75% errors, too. What is a gaussian bell shaped curve for accuracy?
Range estimation errors follow a bell shaped curve, standard deviation about equal to average range est. error, and this data is then fed into trajectory analysis. But one has to get the trajectory analysis right for the system to work.
Nashorn without range finder should get more than 10% hit probability at 2000m after several shots at same stationary target.
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Please also note that the preceding post did not mention that low speed HE rounds generally pack alot more TNT than higher velocity HE (U.S. 76mm HE vs 75mm HE), so lower velocity is not only more accurate but generates more casualties.
A ground target can be a bunch of infantry standing in the open, crouching, lying, running, sitting against a tree, etc. Or hiding and shooting from narrow slit trenches on level ground.
This is a ground target.
If infantry is behind a 3' high stone fence and you want to blow them away from 750m range, is the higher velocity HE accuracy sufficient to hit the fence or is a nice arching 75L24 shot the answer> Depends.
If it is windy 75L24 HE first shot will be blown astray more than 75L70 HE, but this is easy to correct for on second shot if major gusts are not an issue.
Hitting ground points with HE seems to favor close support guns like 75L24, hitting vertical targets may favor 75L70 HE.
HE beaten zone is calculated by Germans and makes sense, low velocity HE has less scatter on ground (in long direction) than higher velocity. This is why short howitzer like guns used on tanks, and why the very low muzzle velocities with British 3" and 95mm close support guns were okay in field.
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German data on HE "beaten zone", area where 50% of HE shots will land if range to a ground target is perfectly estimated, clearly shows that low velocity HE is more accurate than high velocity HE.
This is not my speculation, it is a fact.
Flat trajectories are impacted more by random scatter than curved trajectories when it comes to landing on the ground.
It is not the easiest thing to grasp but it is so.
This is why low velocity guns are better at putting accurate fire down on a ground point than high velocity.
Make a drawing of a straight-line shot from a tank gun barrel to a given ground point and then the same tank shot with a curved trajectory, and then lift both trajectories the same amount vertically, but a small increase. The straight-line trajectory moves further away than the curved trajectory. Is so?
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One of the odd things about accuracy is that flat trajectory guns are very good at hitting vertical targets but stink when it comes to landing HE near a specific horizontal ground point.
German ballistic data shows vertical dispersion greatly effects the ground fall of high speed HE rounds, and has less effect on low speed HE. So if one wants to land an HE round within 20' of enemy infantry, use 75L24.
If you want to hit a 4' high target at 800m on the fly, use 75L70.
Short guns with low velocities can have superior accuracy against ground point targets. This may be what was meant in the reference to 75L24 accuracy.
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True about gunner factor, the post was discussing how projectile and gun factors fed into the equation.
Having someone who aimed true and someone else who estimated range well could do wonders. Alot of factors. Yup!
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Competent Nashorn crews take advantage of chaos and use it to their advantage. Bracketing takes the human tendency to error and mechanically reduces the errors by small bits until one "zero's in" (although not to 100%).
Cool nerves and bracketing reduce errors and boost hit/kill chances. Should a game deny this, the calm cool kill of the true professional.
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Main factors influencing accuracy are:
1. VELOCITY
high velocity flattens trajectory, since round moves further for same gravity drop. flat trajectory means that when range estimate is in error (most are), height of round doesn't change as much so probability of a hit stays high.
2. WEIGHT
Softballs can be thrown many times further then a ping pong ball even though ping pong is smaller and lighter. Heavy things carry better due to momentum which requires less velocity loss for same energy loss.
3. NOSE SHAPE
Uncapped rounds are pointy but not too pointy so they don't break and bend on angled hits. ballistic caps (BC) lower air resistance, so BC rounds lose velocity and penetration slower than uncapped AP if other things are equal.
4. DISPERSION or SCATTER
Jentz' figures are hit % when range estimation error is zero (almost never happens) and percentage is number of scattered shots within a given shape. Scatter is usally secondary to other factors, except in case of APDS where high velocity and flat trajectory were ruined by highest scatter of any round during WW II (not every shot, but enough to have Jentz call WW II APDS "not particularly accurate".
5. WEIGHT TO FRONT AREA RATIO
Weight is carrying power (remember ping pong balls), diameter squared is indication of air resistance. 76 HVAP carries tungsten sabot in big lightweight carrier, 76mm APDS discards sabot and flies with about same weight as 76 HVAP tungsten but alot smaller diameter. Result, 76 APDS loses velocity a heck of alot slower than 76 HVAP.
76 HVAP will be more accurate than 76 APCBC at long range due to flatter trajectory, even after faster velocity loss is considered because HVAP starts at 3400 fps, APBCB at 2600 fps.
152mm APBC has 108#/6"squared, for 4.2.
37mm APCBC has 1.92#/1.5"squared, for less than 0.9.
Velocity alone doesn't but accuracy, APDS scatter spoils things. But small scatter doesn't buy accuracy either. 75L24 may have same scatter as 88, but 75L24 trajectory is so curved that a 50m range estimate error at 500m may result in a miss, while one aims the Jagd Tiger 128mm at 900m range and hits everything inbetween because trajectory is so flat.
Jentz' figures are not field accuracy, they just tell one how wide the scatter is if the aim is kept constant. That's all dispersion probabilities mean. They don't suggest the accuracy on the second or third shot, because the third shot at 1500m may not have the range setting close to target range, so scatter won't be centered on the target but on some point outside the target.
Dispersion is part of the accuracy picture, and it limits max hit % at 2000m and 3000m and 4000m. If one has a gun sight that exactly predicted range out to 5000m but 50% of the constant aim shots at 5000m were greater than 2m from hit center, 5000m hits would be rare.
Heavy rounds like 152mm APBC carry well but are shot at slow speed (600 m/s) and the rate of fire is about 1.5 shots per minute. 100mm APBC weighs about 34# and is fired at 900 m/s, but rate of fire is also lower than a 75mm gun. 122mm on IS might shoot at 1 to 2.5 shots per minute, although a 55# APBC round shot at 2600 fps will carry alot of energy to 2500m and beyond.
Steel has a difficult time holding together above 3000 fps, tungsten resists high velocity better and small tungsten cores can outpenetrate big steel plugs without all the recoil, which increases the penetration that a given gun can obtain.
Tungsten has bad slope effects because high hardness brings with it brittleness 76 APCBC or 17 pounder APCBC has 2.5 slope multiplier against Panther glacis, 80mm at 55° from vertical is equivalent to 200mm at 0°.
Tungsten HVAP has 4.3 slope multiplier against Panther 80mm glacis, for 344mm at vertical equivalent resistance. HVAP may outpenetrate 76mm APCBC, but 55° Panther glacis has 1.72 times the resistance against HVAP!
German APCR used to stick in the guns, according to Jentz. And rounds were so light and carrier was so large that accuracy and penetration fell off rapidly with range.
Accuracy depends on alot of factors and velocity, or scatter or penetration alone can be misleading in certain cases.
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We don't mess with ballistic coefficients, we have tables for velocity vs. range.
88 APCBC from Tiger loses a smaller % of velocity with range than Panther 75mm due to two factors:
heavier rounds lose less speed with range for given air resistance (reason why a heavy softball can be thrown further than a near-weightless ping pong ball).
faster rounds lose energy and speed faster, since air resistance proportional to velocity squared.
20mm rounds lose velocity very fast, 152 very slow.
Another factor is shape, which we don't deal with due to velocity vs range tables. Rounds without caps have points but can't be too sharp since they would not penetrate angles very well. Ballistic caps streamline round so it has less air resistance.
Sherman 75mm APCBC (armor piercing cap, APC, with ballistic cap, BC) loses penetration much slower than 75mm AP although both shot at 2030 fps from Sherman. However, 75mm AP penetrates 113mm at 0m, 75 APCBC only 91mm. 75mm AP could hole Tiger front at close range!
Difference is due to two factors:
75mm AP is solid shot, and HE burster costs a round about 8% to 10% of penetration. APCBC caps absorb energy upon impact without adding too much against homogeneous armor, so caps lose about 10% to 12% of penetration.
So why use a cap? 75mm AP shatters alot against thick armor (armor thickness equal to or greater than projectile diameter), and caps may decrease probability. Caps increase penetration against face-hardened armor, so 75 APCBC penetrates more face-hardened armor than 75 AP, and APCBC penetrates more homogeneous at long range due to slower velocity loss.
Note that 75mm AP shattered at impact velocities below 2000 fps. U.S. tests showed that 75 APCBC didn't shatter too often.
Soviets use 100, 122 and 152mm rounds with ballistic caps that carry alot of their penetration to long range, due to heavy weight and cap. One factor that tells if a round is good ballistically is weight over diameter squared, since weight indicates if round has carrying power and diameter squared suggests relative air resistance.
152mm APBC is 108 lbs divided by 6" squared, or about 4.2. 37 APCBC is 1.92 lbs divided by 1.5" squared, or less than 0.90. U.S. 76mm APCBC has 15.44 lbs divided by 3" squared, for 1.75.
Big rounds carry well, like 152mm APBC, but SU 152 could only get out between 1 and 2 shots per minute. Alot less shots per minute than an M10.
Good questions, hope this fills the bill.
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Accuracy as hit probability % is a function of two factors, velocity to a given range and dispersion.
An 88L71 fires at about 2.6 times the muzzle velocity of 75L24, so the 88 trajectory is much flatter. Flat trajectories mean that the ammo flight path doesn't change as much if the range estimate is in error, so a higher percentage of hits with expected range estimate errors with flat trajectory.
The Jentz figures are for tests where the range is known, and the round to round scatter is measured and compared to a standard target size. Jentz accuracy says that when the 2 pounder and 88L56 have been set to the exact range of the target, the 88 will hit more often.
When range estimation isn't 100% correct, most shots, the 88 will be close to the target more often than 75L24. Having smaller scatter at constant aim (Jentz figures) means that when range estimate puts aim at edge of target, fewer shots will scatter off the target.
Trajectory is primary factor effecting accuracy, scatter plays a secondary but important part.
Although 17 pounder APDS with its' high speed would not have a flat trajectory if scatter was high due to sabot pieces sticking on round, which they did. In 17 pdr APDS case, scatter could totally destroy flat trajectory effect (at Isigny, 7 of 24 17 pdr APDS shots at Panther missed from 200 to 800 yards). In most cases trajectory and velocity rule.
At long range, scatter limits the accuracy one can obtain. Even if aim is right on target a good percentage of shots at 3000m will scatter off the target.
Scatter is due to differences in ammo powder charge and weight, gun recoil and tank reaction to shot, barrel reaction, etc.
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Regarding the original message on accuracy,it appears that 500m hit percentages are limited by tank gun elevation on German heavy tanks and Sherman, guns that have to shoot at targets below the barrel have to use a very curved trajectory which reduces accuracy. High set and slow guns like 75L40 on Sherman suffer even more, trajectory is curved to start with due to low speed and shooting at lower target center of mass introduces even more error.
Our results for shots beyond 1000m probably will hold if target is within 0.7m of gun barrel, otherwise things might change.
Could Nashorn get more than 10% hit probability on a shot at 2000m after repeated tries? Start at 10% range estimate error and range error quickly decreases through bracketting to much more than 10% hits per shot. With range finder 2000m becomes a high % shot after bracketting.
At 3000m Nashorn is limited by random scatter from shot to shot, so 1,000 shots won't improve over 8th shot. Even if range is right on at 3000m, misses will occur on a regular basis (and this does not consider wind gusts or crosswinds).
One response to a post on weapon cant (one side of gun higher than the other) pointed out that defenders usually pick locations where one wheel of gun, or track of track, won't be higher than the other and lead to lateral errors on long range shots. Nashorn crew takes time to set up on level ground, breaks out range finder or scaled map of landmarks, and waits for enemy.
Shermans or IS tanks burst into open, some might stop and fire back from terrain with side slopes, first shot misses that are quickly corrected. So many advantages to defender and the number keeps going up.
There is a story of a single Jagd Tiger that decimated a large number of Shermans. Knock-outs can be more than just a gun and armor, picking the right terrain (no cross slope), long and clear fire lanes and having landmark distances but big advantages. If 128mm gun was lower than Shermans, this would also add slightly to accuracy at long range (though it might not have been known to be a bonus).
Although no wargame can claim highly accurate or even highly realistic figures, there are certain hit % ranges that are reasonable and can be supported. The trick is to present reasonable figures.
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An earlier post asked it target elevation could increase accuracy. Elevation of the aim center relative to gun barrel was tested using following scenario:
Target is a fully exposed M4A1 Sherman. Aim point is center of mass (firer tries to drop round on middle of observed tank mass).
Panther and M4A1 Sherman (75) try to hit the target on the center of mass, with average range estimation error of 25% distributed statistically (bell shaped distribution curve varying from 0% error to 75% error).
The higher a target is relative to the gun barrel, the higher the hit %:
Target M4A1 at 500m
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Panther Accuracy at 500m
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Aim point is +2.1' higher than barrel, 99.5%
aim point elevation equal to barrel, 97%
aim point -2.1' lower than barrel, 91%
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Sherman 75 accuracy at 500m
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aim point +2.1' above barrel, 83%
aim point same elevation as barrel, 74%
aim point -2.1' below barrel, 67%
Conclusions
Target elevation matters alot at 500m.
When target aim point is below level barrel, trajectory is aimed downward and gravity greatly curves trajectory, lowering accuracy. When shot is aimed at higher target, trajectory is flatter around target range and range estimation errors aren't as critical.
Slow rounds are impacted more than faster, flatter trajectories due to greater curvature of Sherman 75 flight path.
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M4A1 target at 1000m
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Panther accuracy
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33% with target aim point +2.1' above barrel
30% when target at same elevation as barrel
29% when target aim point -2.1' below barrel
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Sherman 75 accuracy
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21% when target aim point +2.1% above barrel
21% when aim point equal elevation to barrel
20% when aim point -2.1' below barrel
This shows that the simplified trajectory equation may not be totally satisfactory for low to medium velocity rounds fired at medium to close range, since simple equation assumes barrel at same elevation as target aim point.
Above analysis also suggests that shooting at small targets introduces two problems, smaller profile causes misses with higher % of range estimates, and lowered accuracy when trajectory has to be aimed downward. And that vehicles such as Hetzer and StuG III, and anti-tank guns (especially dug-in guns), might have better accuracy than a 76mm Sherman due to lower barrel elevation.
At 1000m and beyond, barrel elevation relative to target center of mass is not as critical for elevation differences studied, based on above results.
Panther accuracy at 500m seems higher than in CM, regardless of target aim point.
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Many times my posts state results and leave things at that. Other times they fully document the case,a nd sometimes they beat it to death.
It is difficult to be at the same level for alot of posts.
Did you read what Jentz said about APDS accuracy? About Isigny? We had other firing test results from WW II British sources on APDS dispersion, and it seemed to easily be the most inaccurate ammo used during WW II. At Isigny they aimed at the Panther glacis and missed the entire tank.
Soviet T62's were the first to use armor piercing fin stabilized discarding sabot rounds, smootbore gun so stabilization in flight came from fins that came out after ammo left barrel.
Israeli's noted after 1973 war that many T62 shots came at them sideways!!!!!!!! Discarding sabot of any kind goes thru a long development period.
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Iron Duke,
Against 2m x 2m target at 3000m, average and elite Nashorn crews have following shot by shot progressions:
AVERAGE
1st shot
3%
2nd shot
11%
3rd shot
15%
4th shot
17%
5th shot
20%
6th shot
25%
7th shot
25%
8th shot and thereafter
25%
Dispersion is main limiting factor.
ELITE CREWS
1st shot
7%
2nd shot
25%
3rd shot
30%
4th shot
36%
5th shot
40%
6th shot
40%
7th shot
45%
8th shot and thereafter
45%
Dispersion lower than AVERAGE (half), better at estimating ranges within bracketting procedure.
Based on our statistical studies of what goes on in bracketting, 8th shot is about it for improvements cause dispersion keeps moving rounds around so one can't tell what real range is. The further the range, the less one can tell from a miss about the correction required.
Here is Nashorn using coincidence range finder (5% average error) at 3000m:
1st shot
13%
2nd shot
32%
3rd shot
38%
4th shot
40%
5th shot
44%
6th shot and thereafter
48%
Rangefinder helps get shots close to actual range faster, only boosts max hit score a tad. We have printed hit score sheets for just about every commonplace WW II gun used against tanks, for poor, average, elite and super ace crews (super ace has 5% average range estimate error, or uses a range finder).
Double sided pages allow four crew quality on one page. Page gives chance of landing shot within a 2m vertical height and 2m lateral distance.
We then roll dice using scores to see where shot actually fell on the target tank, and we measure offset from aim point. If you would like to see some typical sheets, e-mail me directly and I'll mail some to you.
We feel that our results are realistic, we checked Tiger 88L56 APCBC against Fletcher story that Tiger crews expected to score hits in 1200-2000m range by such and such a shot, and our results matched up well.
Here's a problem with comparing gravity drop at different ranges and trying to relate it to accuracy.
88L71 APCBC takes 2.20 seconds to get to 2000m, and 1.04 seconds to get to 1000m. Difference in gravity drop when gun is shot without elevation is 18.46 meters. Some people might say that this suggests that difference in shot placement is 18.4 meters (target at 1000m, aim at 2000m).
88L71 trajectory to 2000m has maximum height of 6m, target at 1000m and aim at 2000m max results in an error on target of less than 6m, not 18.4m. Difference is because accuracy analysis must include gun elevation.
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If Nashorn with elite crew in our system can get to within a 50m range estimation error against target at 2000m, not that difficult considering average first estimate will be less than 10% off, or 200m, then trajectory will be on target (0.62m away from center aim point).
With single dispersion for elite crews, everything in really good working order, about 80% of shots will hit at 2000m after gun zeroes in after 5 to 8 shots.
So elite crews could realistically obtain 80% max hit scores at 2000m after so many shots and use of bracketting.
Our hit scores for elite crews can be supported by above logic.
By way, trajectory discussions should be based on an elevated gun that aims at center of target at estimated range, error is then found by checking trajectory height at target. Previous analyses that used zero gun elevation do not test trajectory difference between estimated target range and actual, and result in bogus conclusions.
Mie previous examples fulfilled above scenario.
Real guns don't fire with zero elevation.
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17 pounder APDS slope effects are less than 76 HVAP, and 90 HVAP slope multipliers very close to 76 HVAP at higher angles.
Jentz states in his book, the one that includes tests against Tiger I by British, that APDS was "not especially accurate" (it's on page 12, but I lost my notes regarding the book title). If accuracy is bad then penetration is also bad because both are related to irregular flight path (with wobbles).
17 APDS should penetrate Panther glacis out to 1200m WITHOUT the 0.85 quality factor, if British 30° penetration figures are converted to 55° using British slope effects. At Isigny they failed at unbelievably close ranges.
WW II APDS is not consistently accurate, and Jentz goes further and states it was "not particularly accurate" and had trouble against the Tiger II front lower hull (which should have been penetrated at 1300m, based on comparisons using APDS slope effect at 50° and 0° penetration by 17 pdr APDS).
Panther glacis resistance at 1.00 quality is 80 x 2.75 for 55° to 0°, or 220mm at 0°.
17pounder APDS penetration at 0° works out to be:
256mm at 500m
233mm at 1000m
223mm at 1250m
213mm at 1500m
These are highest British estimates (converted 30° to 0° using 1.24 multiplier).
Following are reduced British estimates found in alternate source:
230mm at 500m
217mm at 750m
205mm at 1000m
Tiger II has 100mm at 50° front lower hull, resists APDS penetration like 220mm at 0°.
Jentz book suggests that when 17 pdr APDS fired at Tiger II, penetration way off test results. Similar to Isigny.
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My results are calculated.
The simplified trajectory equations are on "migh" hand calculator and allow the effect of range estimation errors to be computed using flight time to estimated range, estimated range and actual target range.
To simplify things, "oui" assume that gun is at target center range. For game purposes this is adequate.
Like trajectory analysis, "hour" results seem to vary alot from CM.
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If Nashorn range estimate is off by 50m against a 2000m target, the trajectory will be about 0.62m from target center (average shot with 50m error will be on target, with some scatter about center).
A 100m range estimation error results in a 1.28m error from target center (average shot is just over or under).
A 200m range estimation error (the average for elite crews) will be 2.67m over or under.
First shot +200m estimate error, say a miss.
Second shot -300m estimate error, say a miss.
Third shot within 50m of true range, average shot trajectory on target.
Once the average shot trajectory is on target, misses will still occur but range may eventually be closed even more (when gunner aims at exact range, hit % peaks).
Our figures for elite crews look high, but average crew seems okay. Any comments?
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10% max limit on elite Nashorn accuracy at 2000m seems too low.
Hit scores at 500m often seem too low.
Our stuff is based on trajectory equation analysis using assumed bracketting range estimates and corrections after first shot.
Elite Tiger crews supposed to be within 10% on first shot, so long by 200m on shot #1, on average.
Shot two is maybe 100m short. Correct by adding about 150m for 50m long (although there will be errors in estimating how much over or under).
Good chance for a hit here on shot three, even if estimate is bad dispersion may bring shot onto target.
10% max is way too low for elite Nashorn at 2000m, compared to "hour" average crews.
The trajectory model used to estimate hit % may be too drastic in assessing how estimate errors influence fall of shot. This is why "i" spent the time discussing and clarifying accurate models.
The simplified trajectory equations have been compared to German ballistic data and are comparable, the equations match the Tiger Fibel, and maybe they should be used to re-examine the hit %'s in CM.
Just a suggestion.
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Here are the figures we use for average crew 88L71 firing at stationary 2m high x 2m wide target at 2000m:
1st shot
7%
2nd shot
21%
3rd shot
30%
4th shot
36%
5th shot
40%
6th shot
40%
7th shot
44%
8th shot and thereafter
48%
Results differ from previous numbers cause we're using a 2m wide target on this post
ACE crew at 2000m vs 2m x 2m target
1st shot
20%
2nd shot
46%
3rd shot
59%
4th shot
65%
5th shot
70%
6th shot
70%
7th shot
70%
8th shot
75%
Above results consider effect that dispersion has on accurate gun corrections.
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Since most targets in real world are higher than 2m from hull bottom to turret top, max hit % for 88L71 against Sherman or T34/85 will be greater than listed in previous post.
Sorry for "dizzying" posts. A few people are interested in details, most are not. Skim over the stuff and ignore the baloney if you are so inclined. "AYE" do when "EYE" go thru other peoples' stuff.
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These are the max hit %'s that "wea" allow the 88L71 to have against a 2m high target, usually attainable on 6th or 7th round:
AVERAGE CREW
1000m-90%
1500m-75%
2000m-60%
2500m-45%
3000m-35%
ACE CREW (better maintained guns and sights so lower dispersion, and better able to home gun in on target)
1000m-95%
1500m-90%
2000m-80%
2500m-70%
3000m-55%
The limitation on max accuracy is due to dispersion, which not only scatters rounds but presents misleading shot results (high miss with low range estimate, etc.).
Max Hit Probability
in Combat Mission Archive #3 (2001)
Posted
Lewis,
The concept that low velocity HE may be more accurate than faster rounds against ground point targets may not be an easy thing to accept, and some active tankers who were part of our group left when we pursued the theory ("velocity low is the way to go").