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Shot Dispersion


Hackworth

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does the shot dispersion apply to ALL tanks and vehicles? does it matter if the vehicle is controlled by the AI? Alpha India (in T-80s) was getting first, second, and third round strikes at over 3000m this morning. of course they were killing the hell out of us too. does the dispersion vary dependent on the vehicles? in the M-1 i had rounda that would strike dead on, then the second shot would land way high (no adjustment to the aimpoint made; the first rounds hit), and the next way low of the target. again, no adjustments made. it was really frustrating considering that the T-80's were effing us up bigtime from the same distance with very few misses.

EDIT: note, the cases in point are from a stationary target firing on a stationary target both being on flat ground. in addition, i was dumping lead applied by my lase.

also, does ammo type of the same class, i.e. M829A1 vs. M829A3, influence the amount of dispersion?

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Yupp, shot dispersion appears to be absolutely FUBAR atm, rounds sometimes land 10 meters left or right of target when you'r shooting at ranges around 3000m

Another thing i noticed today is getting really wierd lase returns, I most often use the arm last return on the M1 which means i aim a little low to get a good lase, recently this has started to give me crazy lase returns of 5000m at targets that are at 2900m for example, however if i aim really high it gives me a good return, and by really high i mean lasing with the bottom of the reticule at the top most part of the turret which means the top part of the reticule has nothing but air infront of it, still getting good lase.

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yes, dispersion varies between tanks. currently, russian tank guns are twice as accurate as western guns. and the leo1 rifled gun is also twice as accurate.

the russian gun dispersion might need adjustment, since there's no really solid data on it.

the 120mm smoothbore dispersion should be fairly accurate however.

some army customers have even commented that its almost too realistic.

you'll be able to hit soviet tanks at <2400m with the 120mm L44. with the L55 you can hit at even longer ranges.

the russian tank guns are 120mm L48 smoothbore, and the dispersion statistics was taken from one of the manufacturers sites, (morozov)

but looking at some other data from another site, where they have both ammunition types (L44 120 and L48 125mm)

the dispersion is most likely twice that of the L44.

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that helps clear it up a little. but, i don't really understand why the russian weapons should be twice as accurate. both guns are smoothbore, approximately the same caliber. what's the major difference to cause twice the accuracy?

EDIT: Ah! you edited your post on me Deja ;) i see the comparision between the calibers. i didn't realize the caliber of the russian guns was that much greater. what is the caliber of the M1's gun? been searching online and cannot find it. fprado failed! ;) so did Jane's to be fair...

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No, he answered exactly the question you asked; told you the caliber (inside diameter) of the gun. What you wanted was the length, measured IN calibers. a 120mm L44 would be a 5280mm or 5.28 meter long tube (120x44).

Curiously enough, the Panther of WW2 had a 75mm L70, which despite being L70 instead of L44, has a gun actually 30mm shorter. Length is just measured in calibers because the ratio of diameter to width is more relevent to velocity than a measurement of length alone, I guess?

Incidentally, I thought the 120mm L55 guns and the longer Russian guns were LESS accurate than the shorter 120mm L44, due to barrel whip (has to do with internal harmonics in the barrel, kind of an echo from the shockwave of the propellant) and in particular barrel flex when the vehicle is in motion. I was under the impression that the longer barrels were primarily just for attaining higher velocities.

But then again, it could just be inferior manufacturing techniques. Kind of like how I can shoot half minute of angle groups out of a 16 inch AR10 (that's 7.62mm L53) while my Dragunov (7.62mm L81) has trouble attaining minute of barn. I've never been particularly impressed with Soviet kit.

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Other than it's really strange? No clue. I really can't think of a reason beyond programming error.

I've never used real-life tank lasing equipment, but I've used a lot of artillery rangefinding lasers, and I've never seen anything that would result in a displayed range being longer than the distance to any object actually caught in the lase. I can't think of any combination of intervening obstacles, atmospheric obscuration, reflections, or anything else that would do anything other than present a shorter range, or return an unreadable "bad lase"

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But he was using last return - it is normal (if the terrain backstop is close, or the target is track-down) to lase a little low in this mode.

If the target was fully exposed, and the terrain slopes behind the vehicle allow for a backstop some way behind it which is visible between the suspension, then it is possible theoretically to obtain a bad lase from a low aim point.

OTHO lasing high in this case could produce a clean return from the target, and null return from the sky, giving a good range.

In these cases where I cannot get a clear LOS for first return, and there are problems with distant reflectors and small target size for last return, I tend to offset lase on a good laser target at approximately the same distance or just input a measured or best guess manual range, and then fire a BOT if required.

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We are setting dispersions individually for each round type. We don't have data for all the rounds, they are difficult to find. In these cases we're interpolating the values from rounds of the same type and caliber that were manufactured earlier or later.

I'd like to see some data to back up these wild claims of unnatural accuracy of Soviet guns, especially when they are coming from a team member, and I would appreciate if these concerns would be formulated within the beta team where they belong. If valid data are presented that a current parameter is not accurate it will be corrected, as has been done before. Hyperbole only creates hysteria.

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But he was using last return - it is normal (if the terrain backstop is close, or the target is track-down) to lase a little low in this mode.

If the target was fully exposed, and the terrain slopes behind the vehicle allow for a backstop some way behind it which is visible between the suspension, then it is possible theoretically to obtain a bad lase from a low aim point...

Did u even bother to read my post?

Thats what i do, i lase low when using arm last return, the problem usually shows up on longer ranges, could have to do something with the LOD maybe, maybe the laser just goes straight through the road wheels, gonna do some more testing.

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It's ok Ssnake, we wont get hysterical, the T-80 has always been extremely hard to deal with, so most of us has growned used to it, theese are just observations from us and we have not done any hardcore testing to confirm it, it just "seems" the T-80 is extremely accurate at longer ranges.

We like you and your sim very much annyway :-)

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Yupp, shot dispersion appears to be absolutely FUBAR atm, rounds sometimes land 10 meters left or right of target when you'r shooting at ranges around 3000m.

At 3000m with a standarddeviation (SD) of 0.3 mil about 68% of all rounds will pass through the target plane within a circle of 1.80m diameter; 95% (that is, 19 out of 20 rounds) will pass through a circle of 2.40m diameter from the aiming point, and about 1 out of 100 rounds can still be as far away from the aiming point as 2.70m (all shot deviations are capped at 3 SD).

If the deviation happens to be in height and not to the side, the round can hit the ground hundreds of meters in front or behind the target. If the aiming error is added to be another .5 mil (which actually isn't all that much) you already have an SD of .8 mil, or one out of 100 rounds landing 7.20m left or right from the aiming point. Add a bit of height variation and the round may easily appear to be wildly off.

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It's ok Ssnake, we wont get hysterical, the T-80 has always been extremely hard to deal with, so most of us has growned used to it, theese are just observations from us and we have not done any hardcore testing to confirm it, it just "seems" the T-80 is extremely accurate at longer ranges.

We like you and your sim very much annyway :-)

It's not a question of "like" or "not like". I've been somewhat semi-decent in stochastics at university and I try to be as accurate in the parameterization as possible in our model. If a team member is sowing doubt with irresponsible forum posts with nothing but vague gut feeling I simply can't ignore that. It's a direct attack to undermine the credibility of our effort to present an unbiased model of reality. Whether that is done on purpose I don't know.

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It's not a question of "like" or "not like". I've been somewhat semi-decent in stochastics at university and I try to be as accurate in the parameterization as possible in our model. If a team member is sowing doubt with irresponsible forum posts with nothing but vague gut feeling I simply can't ignore that. It's a direct attack to undermine the credibility of our effort to present an unbiased model of reality. Whether that is done on purpose I don't know.

i sent you 2 emails on the 14th of july. now that i finally have your attention, i hope you'll respond to them.

it'll help solve the question you had about what method the ukrainians used to measure the gun dispersion.

http://www.bumar.com/files/document/248.pdf

http://www.bumar.com/files/document/249.pdf

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Did u even bother to read my post?

Thats what i do, i lase low when using arm last return, the problem usually shows up on longer ranges, could have to do something with the LOD maybe, maybe the laser just goes straight through the road wheels, gonna do some more testing.

Yes, thanks I did read it.

I also explained that it is possible to get a return from the terrain behind the vehicle if the vehicle is track-up, which is especially true if aiming low at long ranges.

Part of the beam passes below the vehicle hull and gives a further return than the true distance.

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I too have noticed uncanny accuracy from the T80s in SBPro PE- often they will attain first-round hits at 3000+ meters, while moving, against hull-defilade M1s and Leos. However, I don't think it's a dispersion modelling issue. My question is: is random gunner error modelled into the REDFOR AI gunners? The gunners do seem supernaturally good. Or maybe I'm just not a very good gunner myself, who knows?

As to the manufacturer's claims on their ammunition... well, I have a hard time believing any company that claims less than 10 feet per second velocity variation on mass produced tank ammunition with very large propellant charges. I have a damned hard time getting velocity variations less than 20 feet per second on handmade match rifle ammunition with powder charges measured individually with an accuracy of one fifteen thousandth of a pound. If their velocity data is so suspect, I wouldn't well trust their dispersion values, either.

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I too have noticed uncanny accuracy from the T80s in SBPro PE- often they will attain first-round hits at 3000+ meters, while moving, against hull-defilade M1s and Leos. However, I don't think it's a dispersion modelling issue. My question is: is random gunner error modelled into the REDFOR AI gunners? The gunners do seem supernaturally good. Or maybe I'm just not a very good gunner myself, who knows?

As to the manufacturer's claims on their ammunition... well, I have a hard time believing any company that claims less than 10 feet per second velocity variation on mass produced tank ammunition with very large propellant charges. I have a damned hard time getting velocity variations less than 20 feet per second on handmade match rifle ammunition with powder charges measured individually with an accuracy of one fifteen thousandth of a pound. If their velocity data is so suspect, I wouldn't well trust their dispersion values, either.

yeah they most likely exaggerated all of the values.

my main point is, they list the T-72's 2A46 gun dispersion as twice to three times less accurate than the 120mm training round.

this is the opposite to SB where the 125mm rounds are twice as accurate as the 120mm ones. now the old 2A46 is a completely different gun to the newer 2A46M. it could even be possible that the current values in Sb are accurate for the 2A46M fitted to the T-80U.

morozov.com's values for example, are listed as 0.2 mils dispersion for the KBA3 gun, which is based on the 2A46M.

http://www.morozov.com.ua/eng/body/kba3.php

anyways, the bumar group is the official supplier of weapons for the polish army.

they're the guys who supplied the polish army with the PT-91 twardy, so i think they are a decently reliable source of information.

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