Do any of these ballistics calculators show MOA error vs input parameter error?

[Walter Haas]

It would be cool if, for the shot you're about to take, the calculator listed the error contributions something like this:

For every 5 yards in distance input error, MOA error is .02MOA or .72inches
For every 3 degrees in temperature input error, MOA error is .01MOA or .22inches
For every 10 degrees in wind direction input error, MOA error is .1MOA or 1.0inches
For every 10 fps in muzzle velocity error, MOA error is .012MOA or 0.2inches

and so forth.

Do any of them do that? That would make you more aware of which parameter inputs are critical. Also, there's probably a statistical method of subtracting these errors from your group so that you are seeing how well you are shooting if you discounted these contributions by a "probable" or likely amount of error. Because even though 1 MOA at 100 yards means 10 inches at 1000 yards, the errors are non-linear. Distance error and muzzle velocity error means time of flight error and the drop of gravity is an acceleration, a squared variable, so every millisecond error will affect your group.

I think you could subtract the probable error of the environmental conditions from a long distance group using this equation:

true MOA of your shooting = [(bullet1_location - MOA_parameter_error- aimpoint)^2+(bullet2_location- MOA_parameter_error - aimpoint)^2+...] / (number of bullets) (a.k.a root-mean-squared function)

That way you're separating how well you're shooting from how well you're reading the environment.

 

[Lowlight]

Ballistic software is not made to help you shoot better it’s there to predict a path under the observed conditions

there are variables not included, it depends on the type of software, 3DOF vs 4DOF vs 6DOF is a variable in what the software can organically use.

You minimize errors based on actual experience, there is no AI to walk you through it

how about when your wind call is wrong but works because you shanked the trigger into the target. You think you did it right and then people wonder why it doesn’t repeat.

education helps you recognize the difference

 

[b2lee]

Most of my best groups are when I do 5 different things wrong and they all line up for a nice tight 5 shot group.

 

[CoryT]

Both AB desktop and Coldbore have a system to look at the effects of various errors. This is not really useful for a single particular shot, but is more of a tool to evaluate how a change to the overall system will affect hit probability. For example, how would improving your ability to read wind from +/- 3 MPH to 2 MPH improve your hit percentage at a given range? What if we increase the velocity by 50 fps? The SD is reduced from 15 fps to 8 fps? This lets us make more intelligent decisions about how to improve our performance by concentrating of the things we can control and the skills we need to work on. You'll find for the most part, that making better wind calls is far more important than in increase in velocity, that your error budget for range depends on the target size and small changes in the environment have little effect.

I use it occasionally during class to show how two cartridges compare or how two shooters skill sets can influence results.

 

[Lowlight]

I would be careful how guys are using the WEZ as they misunderstand the inputs and what it is telling you

There is an article right now on FB running around showing a 1 MOA rifle and a 1/4 MOA rifle shooting the same at 1000 yards based on the WEZ Results

It's helpful but they have to use it correctly,

 

[rtB]

You have to look at the wez inputs. It is what it is. Run wind from 2 to 4, velocity from 2800 to 2850 etc etc. its basically a random number generator with bounds set by input values. Think of it as I guess N will be between x and y. If x and y are off you get crap. The moa of a rifle is only a small percent of the input. Try using fixed numbers - ie wind 5-5, mv 2800 - 2800 - change the moa. If you change everything you get nothing.

 

[Lowlight]

Those images are from an article posted on FB,

The data is wrong, don't care what causes what, it's wrong.

People play with it and then get skewed information because they are doing it wrong

 

[sleeplz]

That picture definitely fooled me than. I dont understand, is the program just completely wrong or are people using it for the wrong application?

 

[rtB]

Once again, you have to isolate variables. Read the text in the image - muzzle velocity 20 fps spread. Imagine shooting with sight height between 1.5 and 2.0 for example. Wind speed and muzzle velocity will be the biggest variables, but every input counts..

 

[Lowlight]

How does a rifle shooting 1/4 MOA have the exact same percentage at 1000 yards as a rifle shooting 1 MOA

If you skew the 1/4 MOA rifle to appear like a 1 MOA it will,

But a 1/4 MOA is probably gonna have a lower SD which is part of it, you can have the same MV but a true 1/4 MOA rifle vs a 1 MOA is not gonna be the same at 1000 yards.

These are NO Wind conclusions in the article.

Part of the problem is the way it looks at the values if you use the same BC and MV it will make it identical, but it's not

This is not my data, I'm just saying people are using it wrong because they are making it appear these two situations ar equal

I know how to use the WEZ, though I use the Error Budget more so in CB 1, vs AB, but it's the same, the Error Budget and WEZ do roughly the same thing

 

[Dthomas3523]

That picture definitely fooled me than. I dont understand, is the program just completely wrong or are people using it for the wrong application?

In simple terms, because they used a 1moa target with zero wind and a perfect shooter assumed.

If you take a 1moa target, with a 1moa gun, no wind, and the perfect shooter......

No shit that it’s gonna hit the target the same amount as a 1/4moa gun with no wind and a perfect shooter. Both the 1moa gun and the 1/4 moa gun are inside the error margin of a 1moa target. You’d get the same data from a 1/16th gun almost.

Now, add a 5mph wind in there. And shooter error who misreads its as an 8mph wind. You’re gonna wish you had that 3/4moa extra error built in.

The author of that article is always online attempting to come across as someone in the know. If I were you, I’d ignore everything from that source.

 

[Dthomas3523]

How does a rifle shooting 1/4 MOA have the exact same percentage at 1000 yards as a rifle shooting 1 MOA

If you skew the 1/4 MOA rifle to appear like a 1 MOA it will,

But a 1/4 MOA is probably gonna have a lower SD which is part of it, you can have the same MV but a true 1/4 MOA rifle vs a 1 MOA is not gonna be the same at 1000 yards.

These are NO Wind conclusions in the article.

Part of the problem is the way it looks at the values if you use the same BC and MV it will make it identical, but it's not

This is not my data, I'm just saying people are using it wrong because they are making it appear these two situations ar equal

I know how to use the WEZ, though I use the Error Budget more so in CB 1, vs AB, but it's the same, the Error Budget and WEZ do roughly the same thing

Yep. This is what happens when it’s so easy to publish data online.

Now we have someone with no real knowledge manipulating the WEZ prediction to incorrectly show there is no advantage to a 1/4 moa gun over a 1moa gun.

And people are eating it up.

 

[rtB]

I guess the interesting question is how can one define a rifle moa and also define a muzzle velocity variance. So it is possible to enter a .25 moa rifle with a 100 fps muzzle velocity spread. Thats a problem...

 

[Dthomas3523]

I guess the interesting question is how can one define a rifle moa and also define a muzzle velocity variance. So it is possible to enter a .25 moa rifle with a 100 fps muzzle velocity spread. Thats a problem...

Yea, they likely didn’t think anyone would be dumb enough to manipulate the numbers and try to post white paper like data.

But, you know how people are.

 

[Lowlight]

It's not hard, but it's also not linear

Just because a guy can hold 1/2 MOA at 100 does not mean that at 200, 400, 800, or 1000

The growth is more like 1.5x MOA then it's compounded by the wind.

Trigger control is the most common problem along with inconsistencies in hold and position. In other words, most people not only tap or slap the trigger but move between each shot changing their position which also has an effect.

So if you say, you have a 1 MOA rifle, the next question should be WHERE ?

100, 400, 800, 1000 ?

Then you can begin to see how things quickly change.

For me, if I was putting in a .25 MOA rifle I would do 10fps SD spread or less, then for a 1 MOA, it would be a 20fps average like noted with factory ammo. After that, you want to consider shooter error maybe use an offset for that, like throw in 20fps extra of SD depending on how you want to calculate it

 

[CoryT]

In this case, the data is setup for testing if a mechanical increase in accuracy would affect downrange results if all other values were equal. Given the parameters, one could instantly intuit the results, you don't even need the software. This is a very poor 'experiment', if it could even be called that. That's not how the tool is used, and if you don't understand how a tool works you should probably not be using it.

You must be careful about the underlying assumptions used in the model. In this case, where and under what conditions do we get 1/4 MOA and 1 MOA? For example, to get a rifle specified at 1/4 MOA to hit a 2.5" circle at 100% at 914 meters, you basically need to set all uncertainty values to 0. Setting muzzle velocity to a 10 fps variation reduces the hit probability to 64%. If you then reduce the mechanical accuracy to 1 MOA, the hit percentage drops to 26%., but a 10" target is 98% compared to 100% for a 1/4 MOA rifle. The 1/4 MOA rifle is 94% on a 5" target and the 1 MOA rifle is now 70% . This makes sense, but look what you did to the underlying assumption. While you specified the rifle to shoot 1/4 MOA, to actually do that at 914m your muzzle velocity variation must be ZERO! If you set the variation to 5fps, you only get a 90% hit rate. I'm not sure you would say that rifle is a 1/4 MOA rifle at that point. At 9 fps you are 64%, clearly not shooting 1/4 MOA with even great handloads. Does a 1/4 MOA system at 914m even exist? If you take a system that performs at 1 MOA under given conditions, that is, it gives better that 98% on a 1 MOA target, why would you expect a change in pure mechanical accuracy to change much of anything at all?

Note also that other variations are not used in the WEZ simulation, like BC variation, aiming error, zero or scope error, etc. If you ask the wrong question, don't be surprised if you get a nonsense answer.

 

[Dthomas3523]

In this case, the data is setup for testing if a mechanical increase in accuracy would affect downrange results if all other values were equal. Given the parameters, one could instantly intuit the results, you don't even need the software. This is a very poor 'experiment', if it could even be called that. That's not how the tool is used, and if you don't understand how a tool works you should probably not be using it.

You must be careful about the underlying assumptions used in the model. In this case, where and under what conditions do we get 1/4 MOA and 1 MOA? For example, to get a rifle specified at 1/4 MOA to hit a 2.5" circle at 100% at 914 meters, you basically need to set all uncertainty values to 0. Setting muzzle velocity to a 10 fps variation reduces the hit probability to 64%. If you then reduce the mechanical accuracy to 1 MOA, the hit percentage drops to 26%., but a 10" target is 98% compared to 100% for a 1/4 MOA rifle. The 1/4 MOA rifle is 94% on a 5" target and the 1 MOA rifle is now 70% . This makes sense, but look what you did to the underlying assumption. While you specified the rifle to shoot 1/4 MOA, to actually do that at 914m your muzzle velocity variation must be ZERO! If you set the variation to 5fps, you only get a 90% hit rate. I'm not sure you would say that rifle is a 1/4 MOA rifle at that point. At 9 fps you are 64%, clearly not shooting 1/4 MOA with even great handloads. Does a 1/4 MOA system at 914m even exist? If you take a system that performs at 1 MOA under given conditions, that is, it gives better that 98% on a 1 MOA target, why would you expect a change in pure mechanical accuracy to change much of anything at all?

Note also that other variations are not used in the WEZ simulation, like BC variation, aiming error, zero or scope error, etc. If you ask the wrong question, don't be surprised if you get a nonsense answer.

Just look at the author. Makes complete sense at that point.

 

[CoryT]

I never even looked up the article, the pic was enough to tell me the author does not know what they are doing. Since there is no link to the page, I'd have to do some kind of search to find it. Way too much like work to bother considering what I'd get.

 

[Lowlight]

Link to Article


Didn't want to link it, but here, I actually know Jon, he was a USMC guy, shot RO when I last down there

 

[CoryT]

Well, I don't know the author, but give the resume on the site it seems clear he does not understand the fundamental flaw in the analysis. Of course, most people either failed or never even took a class in probability and statistics.

 

[Dthomas3523]

Link to Article


Didn't want to link it, but here, I actually know Jon, he was a USMC guy, shot RO when I last down there

I was thinking Cole was the author. At least his name is in it.

 

[Diver160651]

It's not hard, but it's also not linear

Just because a guy can hold 1/2 MOA at 100 does not mean that at 200, 400, 800, or 1000

The growth is more like 1.5x MOA then it's compounded by the wind.

Just to restate, because this is the cornerstone these guys getting fucked up.

Take a 3/4 MOA gun at 100, shooting at an MOA target at 1K with 0 SD & 0 WIND. What happens with the target image growing and shimmering in the distance? Is it a tiny .75moa visual disturbance? If so, the base gun is now 1.5MOA, plus all the other great things like SD and wind variations.

Optically the targets at 100 are not affected the same as the target is at 1000. The premise that you can even visualize the target the same is at the core of the error stacking these guys seem to conveniently forget about.

 

[Lowlight]

The better experiment and there are two immediately I can think of,

1. take two rifles of different accuracy potential, one that shoots like 5/8ths and the other that shoots 1/4 even if the ammo is different, and map the growth at distance. Establish a base group, then walk out and note the variation between the two different rifles with a single shooter.

2. The other experiment, take a new-ish shooter or any level of shooter and under "today's conditions" walk out and see how the group grows and changes at a distance and apply a value to that.

The Human factor is huge and combined with a rifle that is not shooting optimal sub 1/2 MOA groups, see how the conditions increase the variation in group size.

So if you have a 3/8th inch shooting rifle, at 100, what does that same rifle and shooter do at 1000, etc.

 

[Ledzep]

The biggest problem here is how the precision and accuracy of the rifle is defined. My guess is that most "1/4 MOA" and "1/2 MOA" rifles actually produce extreme spreads at 100yd in the .8-1.4" range.

We're good at tricking ourselves. If I shoot a series of 5-shot groups that measure .43, .51, .47, .32, and .26 at 100yd, I have a sub-1/2 MOA rifle. If the next time I go to the range and I shoot .63", .44", .70", .52", and .39", I must just be having an off day or perhaps the wind is gusting out there and kicking a few shots off or maybe I got sloppy with the fundamentals, but I have 2 groups today and the majority of groups from the last trip out that prove the rifle is sub 1/2 MOA.

If I overlay all of the groups from both range days over each other referenced by a mutual point of aim, what was probably produced was a 1.0-1.4" composite group that is what honestly describes the precision/accuracy of me and my rifle. Doesn't sound as sexy as sub 1/2 MOA though.

A factory rifle is going to be more like 1.2-1.8", I'm sure with a handful of exceptions. Don't believe me? go make a 1/2 MOA 20-shot group.

 

[CoryT]

With careful setup, you can put two acoustic targets in alignment so that you can see EXACTLY how a smaller group at close range enlarges at increased distance, and that even without the aiming error of the long range target. Even tiny differences in the bullet BC start to compromise the group at distance where the effect is invisible at 100.

Although, the article does inadvertently make a point, simply buying a rifle advertised to give 1/4 MOA groups won't absolutely improve the results of a shooter only capable of 1 MOA . In fact, if the rifle actually does shoot 1/4 MOA, the shooter probably can't tell.