Accuracy values for the main guns - MBT's.

[Listy]

Hullo kevineduguay1... **Waves**

If you're not, then appolgies. There's been this disscussion over at the DosMBT group, the following reply was given (Edward is talking about the formula used for working out the ACC):

Edward R. Mortimer said:
Y'see, what we have works very well through WWII and even into the
1970's . . . and then breaks down because of the advances in
munitions. The problem is . . . most of that data on munitions in the
last 30 years are classified. Getting a coherent grip on the situation
is not easy. Yes, everyone knows the current formula is not perfect.
But it works well enough when ALL the other variables are used in the
formula (not just ACC, FC & RF, but ALL the variables). ACC is only
representative of firing a generic munition over iron sights, something
which none of these modern tank guns will do intentionally.

Remember, the game has to deal with HE, AP, HEAT, HESH, and all the
varieties of so-called SABOT munitions. Each of which has its own
characteristics (i.e. velocity, drag, etc) . . . but the game demands
that all of them be merged into one identity for the purpose of
accuracy.

So you see it is not that we haven't thought about it, but that we
haven't come up with a better universal formula yet. But to say the
in-game Soviet tanks are better than the in-game Abrams because of a
minor 2 points in ACC rating, yet ignore massive differences in other
ratings that are part of the formula, is ridiculous.

[Fabfire]

Listy said:


Hullo kevineduguay1... **Waves**

If you're not, then appolgies. There's been this disscussion over at the DosMBT group, the following reply was given (Edward is talking about the formula used for working out the ACC):

Appologies accepted. I am not kevineduguay1...

I don't think that a 2 points difference is ridiculous, because it affects not only the Abrams, but also the Leo 2 (up to the A4), Merkava...etc. What seems ridiculous is Western 120mm L/44 being rated as inferior to old Soviet 125mm guns. I am not ignoring other problems with the accuracy formula, it's just that as I have a little more knowledge on tank guns performance, it came to my attention first.

By this formula, who can garantee that even the Leo 2A6 120mm L/55 accuracy of 14 is right? Or even the Challenger's rilfed guns? What we need is a better general formula.

Finally, I still remain with the same doubts I posted.
But thanks for the answer, anyway.

[Mobhack]

We will be having a look at this, but what Ed said in the quotation is very true - you also need to look at the other inter-related values used (such as range finder and fire control).

Cheers
Andy

[JaM]

I dont forgeting FC and Rangefinder. For example if you have a T80UM tank (Crew exp 90)with FC 40 and RF 22(ACC13), you will have better accuracy at longer ranges than M1A1 tank (FC 40,RF22,ACC11 with same crew exp 90),but in reality M1A1 will be much accurate with its ammo such as M829A2 (L/D 30:1) over Russian BM-32,42 rounds (L/D 13:1-15:1).
Accuracy of ammunition is a key factor, that cant be ignored.Much more important than lenght of gun, and is a best measure of technology, gun that can handle those long rods are far superior to those that are not able to fire them. Shorter and more robust rod, the worst accuracy it has over longer distance.First soviet APFSDS rounds were 43-47mm L/D 10:1, their accuracy was bad at ranges bigger than 1500m.

[JaM]

A the other side, i like more your values than those in original SSI Steel Panthers 2. In SSI OOB 120mm smothbore guns had accuracy over 35,125mm guns 25 (same as 105mm)Your lower values are good, the only problem with them that weapons are not modeled correctly. Lenght of gun is not good variable for accuracy of smothbore guns. It has much more to do with kinetic energy than accuracy.My suggested values for tank gun accuracy are:

L/D Value
10.........................11
15.........................12
20.........................13
25.........................14
30.........................15
35 and more........ 16

I reworked most of OOB with those values. Those values dont change much, as those values dont make big difference to your values, but they make older guns( with old ammo ) less accurate than modern guns over longer range as rangefinder and firecontrol value make all guns to have accuracy to 1200-1600m over 90%.With this you should see difference between same tanks with different ammunition,(like T-64B in Russian OOB, T-64B with BM-29 from 1983 will have lower accuracy than same T-64B with BM-42M in 1998 or M1A1 from 1987 with M829 will be less accurate than M1A1 from 2003 armed with M829A2)

[JaM]

link for L/D values of most of soviet APFSDS rounds :
http://armor.kiev.ua/fofanov/Tanks/ARM/apfsds/ammo.html

[Cris]

I agree with the comments wrt the penetrator L/D's but to take only those into account would be a similar issue to taking only Barrel length... both are a factor as is manufacture

Rather than taking to account one factor perhaps a couple of multipliers or an weighted average of penetrator l/d Barrel length..

Just a thought.

[JaM]

Thats true, but there isnt a modifier for technological advancement. On paper, is soviet 125mm gun impressive (L48-50,1700-1800m/s muzzle speed...),but in reality it dont count. First gen soviet APFSDS were very unaccurate.Round of choice was HEAT,becouse it was more accurate and destructive. Western APDS rounds were more accurate than first and second gen. West APFSDS (M735,M111,M774...) I saw somewhere on Tanknet some data, where M60A3 in 1980 firing APDS was more accurate than M1A1 with M827 or Merkava Mk1 firing M111 (87% at 2000m M728, 84% M827 and 73% M111,but M111 accuracy is combat value from "1982 Peace for Galilee",accuracy during tests is always better) So for accurate accuracy :-) formula you need count with much more variables,but many of them are not public domain. (speed loss of projectile at distance,dispersion,quality of discarding sabot etc...)

[Fabfire]

Mobhack said:
We will be having a look at this, but what Ed said in the quotation is very true - you also need to look at the other inter-related values used (such as range finder and fire control).

Cheers
Andy

Thank you. I really think this issue deserves it. I am well aware of the effects of the FCS, but what we are discussing here is the raw performance of the tank guns, in terms of accuracy. JaM really has a point when he makes a link between accuracy and the ammunition used.

Best regards, and thank you for your efforts in providing us with the best SP version ever. I have just received my CD (version 1.012), works like a charm and the improvements are terrific. I strongly reccomend everyone to buy the CD version. It's worth every cent.

[Alpha]

http://www.rheinmetall-detec.com/ind...1454&action=pd

http://www.defense-update.com/products/digits/120ke.htm

notice that ammo is almost as important as the gun itself!