Gun too innaccurate

Testing has been performed which indicates that the extreme spread of the A10's gun is currently 17 mil. All sources indicate that the gun's precision should be 5 mil, 80%. Currently, far more than 20% of rounds are landing outside of a 5 mil diameter.

The best compromise, considering DCS' current limitations in precisely modeling shot distribution, would be to use a Da0 value of 0.0005 in the shelltable which would result in an extreme spread of 5 mil in game. This better reflects the performance of a factory new gun than does attempting to model the minimum performance before maintenance of 5 mil, 80%.

See the tests performed in this thread + the video of an m61 cannon being precision tested.

This has been already reported in 2013, it has also been reported for guns on F5. So far no fix, so take a guess..

https://forums.eagle.ru/showthread.php?t=117686&highlight=gun

https://forums.eagle.ru/showpost.php?p=3222314&postcount=37

This is a known bug. It would be great if we can get a fix.

I sure would like to see this addressed. It takes about 5 seconds to correct the lua file. There's no reason we've had to wait years for this. Mods are great and all, but they aren't MP compatible.

+1 Just get all your friends on it, eventually they will have to take notice, keep bringing it up

this has been reported on the f-15, f-5, f-86, etc. so if all the guns are "wrong" has anyone ever stopped to ask if the units are really in mils or are we just assuming?

this has been reported on the f-15, f-5, f-86, etc. so if all the guns are "wrong" has anyone ever stopped to ask if the units are really in mils or are we just assuming?

The A-10C shows the estimated impact points ("BATA"? those little circles that appear in the HUD) which are supposedly representing those 5 mils - which is consistent with the measurements of the other HUD symbology. The actual impacts are occuring a lot way outside of those predicted impact points.

There were tests performed and result videos posted by the 476th guys back then.

Yes.....Always frustrating. This would be a great thing to see fixed ASAP

Yup. I remember the podcast from September 2016 with retired A-10C pilot Pete Olsen who said the Gau-8 round was designed to go through a T-72 at 1.2 NM (or something along those lines, I can't remember). After hearing this I jumped into DCS and tried to replicate it and boy it was clearly not in line with what Pete said. I found that I needed to set the value to 0.0009 in order to kill those tanks at the advertised distance.

For those who weren't aware of the issue already, here is what you need to do:

Find the text file named shell_table.lua located in C:\program files\eagle dynamics\DCS World\Config\Weapons

In this .lua file search for gau8, find the line Da0 and replace the current value by 0.0009 (or 0.0005 if you want to go with what the OP said).

Do that for the three different gau8 round types listed and you're done.

Accuracy tests seen here by modifying lua file for different accuracy values and measuring dispersion with the F-5's 40 mil diameter gunsight + actual M61 Vulcan accuracy test video (same accuracy as the M39 200mm cannon on F-5)

https://forums.eagle.ru/showthread.php?t=198157

Just being pedantic here but:

The tightness of the grouping -> Precision

The distance of grouping from aim point -> Accuracy

Just being pedantic here but:

 

The tightness of the grouping -> Precision

 

The distance of grouping from aim point -> Accuracy

You're absolutely correct. It's become a colloquialism to refer to "precision" as "accuracy" unfortunately, and I was afraid people wouldn't know what I was referring to.

Thanks for the correction.

New information incoming. I just discovered that it is possible to freeze the aircraft using active pause, decelerate time using alt z, and shoot the cannon in slow motion with no movement of the aircraft. This will make the next videos posted here as accurate as if the aircraft were stationary on the ground!

Are there variations on how different parts of the world interpret mils? It's stated many places that the GAU-8 puts 80% of rounds fired in a 20 foot circle at 4,000 ft. I know this is contradictory to Dennis Jenkins claims of a 40 foot circle, but he's about the only source I can find citing 40 feet vs 20 ft. How far off of 20 feet is it in game?

Are there variations on how different parts of the world interpret mils? It's stated many places that the GAU-8 puts 80% of rounds fired in a 20 foot circle at 4,000 ft. I know this is contradictory to Dennis Jenkins claims of a 40 foot circle, but he's about the only source I can find citing 40 feet vs 20 ft. How far off of 20 feet is it in game?

Yeah, Jenkins is just plain wrong. 5 mil, as it's used in the US, is 20 feet at 4000 ft. 1 mil is equal to 1m at 1km or 1 ft at 1000ft. Not difficult math.

Also, I want to see where the original source got the info for 5 mil, 80%. I'm nearly certain that that's a maintenance figure describing the worst a gun can perform before requiring repair/replacement. This video of a new m61 being tested seems to bear that out. The M61 (used on the F-15, F-14, F-16, F-18, etc) is sourced as shooting 8 mil, 80%. The example in the video is tested the same way as one in service would be tested and shoots much better than 8 mil, 80%, with only 1-5% of rounds outside the 8 mil circle.

No wonder if the cannon has a wide blast of shots. According to me we must also consider the fact that it is a rotating cannon so the projectiles are also subject to centrifugal force and tend to move outwards. "Centrifugal force is a force that appears to act on a body that moves with circular motion" ... their considerable weight accentuates the effect or even the speed of rotation of the weapon would affect, I believe that you do not can avoid this phenomenon if not firing from a closer distance.

No wonder if the cannon has a wide blast of shots. According to me we must also consider the fact that it is a rotating cannon so the projectiles are also subject to centrifugal force and tend to move outwards. "Centrifugal force is a force that appears to act on a body that moves with circular motion" ... their considerable weight accentuates the effect or even the speed of rotation of the weapon would affect, I believe that you do not can avoid this phenomenon if not firing from a closer distance.

And yet the documents state "80% within 5mils".

And about centrifugal forces as such - they act on the projectile only as long as they are inside the barrel. It seems possible, that this may cause some sort of of off-center trajectory in relation to the barrel bore line, but it would be the same for every round fired (within mechanical tolerences). Remember, it is only one barrel fireing at a time and that barrel is always at the same position when it fires. So, that effect may need some CCIP windage adjustment, but would not explain a significantly larger dispersion as such, imo.

This would be easily fixed by simply changing one variable

Why isn't it fixed yet?

This would be easily fixed by simply changing one variable

Why isn't it fixed yet?

In fact, ED should give us an answer

Weekend News 13/03/2020

"The GAU-8 isn't getting left out either. We updated our information from General Electric which diminishes round dispersion by approximately 1.5 times. We know that many in the community have been complaining about this for some time and with this latest data backed correction the Hog will deliver even more tank-busting fun to our faithful users. Thank you again for persisting."

https://forums.eagle.ru/showthread.php?p=4244106#post4244106

Thank you ED!

Weekend News 13/03/2020

 

"The GAU-8 isn't getting left out either. We updated our information from General Electric which diminishes round dispersion by approximately 1.5 times. We know that many in the community have been complaining about this for some time and with this latest data backed correction the Hog will deliver even more tank-busting fun to our faithful users. Thank you again for persisting."

 

https://forums.eagle.ru/showthread.php?p=4244106#post4244106

 

Thank you ED!

That's good to read. With the 2.5.6 update, the accuracy of the GAU-8 seems to have taken a step in the wrong direction, so its good to see they're working on it. :)