Devs-Question about rounds dispersion

[SlapHappy]

There is a rating for the guns and ammo which relates to the "tightness" of the dispersal pattern modified by gunner quality and other factors, correct? So the light machine guns have the same rating as the heavies? (around 5-6 for 7.92 ammo).

Also, the heavier calibers have a lower number (tighter) pattern? Am I understanding this correctly? Weren't the MG-34 and MG-42 in heavy role used with optical sights with around 4x magnification? Wouldn't this effect dispersal pattern independently of the actual velocity of the ammo?

Also, would increasing the number beyond it's base figure "loosen up" the spread even more. And if it does, will the rounds spread out on the vertical or horizontal plane? Or both?

[Fifty Cal']

I'm no Dev but......

A machine gun on a tripod will have a smaller "beaten zone" than one fired from the shoulder just because the gun is "held" tighter, the beaten zone, or "Grouping" is, in effect, a circle in the air, that translates to an actual oval on the ground.

A M/G in a fixed vehicle mount will "shoot" very similar to one on a tripod, whereas a M/G on a "pintle" mount will be more like one fired from the shoulder.

Increasing the number, should, increase the size of the circle, "Grouping", and thus the oval beaten zone.

Main gun armament accuracy is effected , mostly, by barrel length but also by the type of ammo fired.

Is that what you were after?

.50

[Jeff Duquette]

I think this question is well worth a bump, particularly considering the complaints about the games antitank guns and some folk’s perception of ATGs capability against infantry (see the sniper ATG thread). I don’t know how the game details this sort of thing, but would enjoy reading about how this sort of thing is modeled by the game.

Final Hit probability is of course a function of a number potential error sources. Error budget; or dispersion; or round-to-round variations (whatever phrase a person might like using when they are referring to shot spread) is typically broken down into systemic errors, constant errors and human errors.

Systemic dispersion or inherent dispersion or systemic error: This is a random error source that is always gonna be there. Moreover it doesn’t matter how much training you give a guy or a crew, you will always have inherent\systemic shot dispersion. This is caused by vibration or minor contrasts in how the gun or gun carriage distributes shock or stresses from firing; and/or minor contrasts in projectile weights or projectile shape; minor contrasts in propellant burn rates or contrasts in the arrangement of propellant grains between different cartridges, etc. Most of the hit probabilities one sees in books by Jentz and the like, or in firing tables or schusstafeln is based solely upon systemic dispersion.

Constant error sources: This includes things like a steady cross wind; or propellant temperature; or air temperature; barrel wear, minor variations in barrel rifling and barrel alignment, etc. These things will result in variation between the location of the predicted\desired MPI and actual MPI -- i.e. difference between where you are aiming relative to the centroid of a shot grouping. But unlike systemic error sources, constant error sources can be compensated for. For example ballistic tables for artillery will invariably include correction tables for differences in air temperature, or propellant temperature, barrel wear, etc. Zeroing a weapon can compensate for minor variations in barrel "straightness". Bore sighting is a form of compensation for a constant error source...etc..

Human error. This can include aiming and sighting related errors; incorrect range estimates, lead errors, blah, blah blah...

Any one of the above contributors to the error budget can be further subdivided or detailed. For example a human's aiming error may be the result of poor visibility, or it may be a function of a poorly trained soldier that doesn’t understand how to use his front and rear sights; or it may be nervous energy\pucker factor that affects a soldier’s aim. Etc etc etc

Final hit probability is than a direct function of the error budget combined with target size and target movement.

[SlapHappy]

After looking at some of the data for a bit, it seems that there are 3 primary data elements that affect grouping

KDistance - Which seems to be a modifier. It's value is always less than 1.

Grouping Dist - Which seems to be a baseline in meters.

SizeTargetForGrouping - Which seems limited to two types man-sized? or 1.8 and vehicle? or 9. All the small arms are based on the 1.8 value, while shells are based on the 9 value.

Machine Guns are all lumped under one heading at least for these variables. There is no light or heavy differential. However, HMG appears on a separate table which uses an index of 9 for SizeTargetForGrouping along with the tank/gun shells. There is also a pistol, SMG, and Rifle group. Of course, there might be other variables not in this formulae which affect the final value as well.

[FinnN]

Also for each gun there's a minimum and a maximum aiming distance as well as a maximum range, a dispersion at 1000, an aim radius for various distances, a series of 'LinesH' and 'Lines' and a series of penetration values. There are also tables for different types of weapon aiming at different types of target. Obviously all these could have an effect, but which ones are used by the game engine and for what I'm not sure. For example the grouping stuff above - is it for damage? For targeting groups? A modifier for morale effect if one goes off next to you? Projectile dispersion?

Have fun

Finn

[Jeff Duquette]

Originally posted by SlapHappy:

After looking at some of the data for a bit, it seems that there are 3 primary data elements that affect grouping

KDistance - Which seems to be a modifier. It's value is always less than 1.

Grouping Dist - Which seems to be a baseline in meters.

SizeTargetForGrouping - Which seems limited to two types man-sized? or 1.8 and vehicle? or 9. All the small arms are based on the 1.8 value, while shells are based on the 9 value.

Machine Guns are all lumped under one heading at least for these variables. There is no light or heavy differential. However, HMG appears on a separate table which uses an index of 9 for SizeTargetForGrouping along with the tank/gun shells. There is also a pistol, SMG, and Rifle group. Of course, there might be other variables not in this formulae which affect the final value as well.

Excellent work Slaphappy.

[Jeff Duquette]

Originally posted by FinnN:

Also for each gun there's a minimum and a maximum aiming distance as well as a maximum range, a dispersion at 1000, an aim radius for various distances, a series of 'LinesH' and 'Lines' and a series of penetration values. There are also tables for different types of weapon aiming at different types of target. Obviously all these could have an effect, but which ones are used by the game engine and for what I'm not sure. For example the grouping stuff above - is it for damage? For targeting groups? A modifier for morale effect if one goes off next to you? Projectile dispersion?

Have fun

Finn

Finn:

What are you using to look at the games data files?

Thnx

Jeff

[FinnN]

I'm using DrJones' tool - it's his so it's up to him to distribute it or not I guess. If you check your e-mail though I've sent you the contents of some sample .ini files related to this thread.

Have fun

Finn

[Jeff Duquette]

Thanks a bunch. Got your email. I'll give him try.

Best Regards

Jeff