Testing E Target Accuracy

[Bindi2]

By changing the H or W you change the sensor readings which give the x and y. This how you correct the target.

 

[243Mendoza]

By changing the H or W you change the sensor readings which give the x and y. This how you correct the target.

how can you get a stable value for H and W when errors change for every shooting session because of different conditions.

How many iterations of H and W did it take for one day at the range?

 

[Bindi2]

Two of us did it in one session over multiple ranges as the further back you go so the finer the adjustments become in the algorithm hence the 1mm achieved repeatable. Random recordings after that is any thing out side the true error. You will see them when you compare the monitor to actuals. If you only ever use open face targets you will never know the differences that occur between open and closed systems. You will just wonder what went wrong with that shot or shots because the monitor is your eye. In steady conditions shooters adjust to the sighters and go all good. Drop offs and switches can show differences. The more correct the true error is the better the target performs..

 

[243Mendoza]

By changing the H or W you change the sensor readings which give the x and y. This how you correct the target.

This correction implies that there is something wrong with the sensors.

 

[Bindi2]

This correction implies that there is something wrong with the sensors.

No it fine tunes the target. Your measurements may not be perfect. Been there done that ripped my hair out sat down thought about it tried the H W adjustments. I think the algorithm is the problem as it is the distance that fines down the accuracy then with adjustments to the H and W corrects it. I have no other explanation it worked for me. What all this means is test your target at the longest range you have then fiddle with the H and W to see if you can improve the recording. When you have found a constant error that is the true error for that target.

 

[6BRinNZ]

If I understand what you are saying about H and W. This is what SMT have on their website under the accuracy section. Please measure your horizontal ("WIDTH") and vertical ("HEIGHT") spacing to within 10mm.

They list this as the most important.

perpendicularity of chrono mic to target face
This is the single most important item to get correct.

 

[Bindi2]

If I understand what you are saying about H and W. This is what SMT have on their website under the accuracy section. Please measure your horizontal ("WIDTH") and vertical ("HEIGHT") spacing to within 10mm.

They list this as the most important.

perpendicularity of chrono mic to target face
This is the single most important item to get correct.

yes. And Changing the H or W 1mm shifts the impact recording. A 10 mm shift can be a huge movement at close ranges.

 

[GSS]

In steady conditions shooters adjust to the sighters and go all good.

Very Interesting Conversations,
following along as best I can as a non scientist / mathematician but interesting none the less when it is discussed and applied constructively.

I like the part that I quoted above best.
Another quick Simple Man / Average E target Joe perspective diversion from the tech talk...

Like the shiny brand new 2014 Taurus SHO I spoiled myself with back around my 55th yr birthday purchase. It probably has a gazillion computers and parts and pieces designed to work in harmony to allow it to get 365hp and 350 ft pounds of torque out of a six cylinder, with lane assist, collision warning, blind spot warning heated and cooled massage seats and many other goodies to boot while still getting 27mpg highway,,,

I don't necessarily concern myself with what went into the design and what every computer is doing and how it is working as I drive it.. I don't need to look under the hood every time I step on the gas, the brakes or put the massage seat on to watch it do what is going on in the background to make it do what it does.

I just enjoy driving it....
I can get there fast or I can get there slow but it gets me where I want to go.

Same for E targets, like I said above
I'm a simple Man,
I put the e targets up, shoot at them and compare what I see on paper to what I see on the tablet.
I especially like to go by the shots that are right on the line, just in or just out if I really want to get precise.
I don't draw any grease pencil grids or anything complicated ( to me ) like that, I just go by the rings on the NRA Approved paper target.

Then I just want to drive it practicing to improve my ammo and marksmanship skills and using them in organized NRA and CMP Competitions working to grow the sport. Hopefully the NRA and CMP deem these affordable systems that are very much quite good enough for what we do acceptable as they develop the Official Certification Procedures in the very near future.

I am certainly not going to have people in the pits with magnifying glasses and calipers pulling the targets down measuring the exact coordinates of every shot.
All of us in the matches will shoot our sighters, adjust off what is shown on the screens and go for as many 10's and X's as possible in whatever the range conditions are for all of us that day. We will all get identical pit service. Unlike with humans in the pits.

Sorry for the diversion from the interesting / constructive tech talk and Cheers to all working to grow the sport.
George

 

[spclark]

I am certainly not going to have people in the pits with magnifying glasses and calipers pulling the targets down measuring the exact coordinates of every shot.

That's the crux of the issue here I believe:

With paper targets there's an artifact left behind - the holes - once a bullet has passed thru the paper.

You can see it, measure its distance from a scoring ring or another hole, cut it out and take it home to mount on your wall if you want to, along with the others than have been created over time as you've fired round after round, trying to stay centered up and adjusting for wind conditions all the while.

With ET's all you have are pixels forming an image on a screen, or maybe toner particles fused to a piece of paper (NOT what you were aiming at!) or a set of spreadsheet numbers that were used to calculate where those toner bits were placed by a printer or those screen pixels.

It's a LEAP OF FAITH to believe those numbers represent the same thing as those holes in the paper target you were aiming at, because in truth they don't.

They CAN'T.

They're not the same thing whatsoever.

Whether a paper target was held rigidly in place during a string of fire isn't commonly addressed. Targets move about in the wind, just like bullets flying down range. Target backers inevitably aren't flat either, targets themselves aren't dimensionally perfect yet we have accepted the truth of the artifacts they record as some kind of absolute.

So swapping ET's for paper targets requires an entirely unfamiliar - perhaps uncomfortable - mindset for acceptance. Trust in The System if you will. Trust that, all else concerning bullet paths aside, the results returned are as accurate a representation as possible of where in the calculated space (between whatever sensors are arrayed to record their passage) your bullets have been passing as they arrive and get noticed.

It comes down to numbers, not holes.

How those numbers are obtained. How reliable they are. How repeatable the system is over time to determine where those bullets are as they pass. It's not about a physical representation, an artifact, left behind in something that didn't have a hole until a bullet went thru it.

I own and use an SMT G2 system. It serves my needs for practice. I accept that what I see on screen is not the same as the paper target I aim at, yet because I can see that my sight changes and position flaws are reflected in how those pixels array themselves once the last shot I've fired is scored, I've come to trust it in other words as being 'good enough' for this purpose. At the same time I trust what the SMT system installed at Winnequah tells me when I shoot there, either in practice or for an event.

Truth be told I have yet to shoot on any other available ET system; they're too distant from me where installed, and I can't afford to buy one of each either for use closer to home. Besides I know they all have their own drawbacks.

What I'd like to see here is a reasonable discussion of what other principles there are in physics that might be used to achieve as practical and affordable ET system as what's out there now, that won't have the drawbacks associated with data acquisition captured by acoustic sensors.

From what I know at present there's nothing yet out there.

Yet I intend to keep an open mind.

 

[sdean]

Just about time to bring out the dead horse here and start beating.

 

[GSS]

Probably the best thing is,
Not every range will be going to Electronic Targets this year or likely ever...

If you despise, fear or will never trust ET's and like your paper targets and pulling pits
You can keep your paper targets and select the ranges you go to that still use paper.

If you can go shoot a match on ET's without lying awake at night wondering and worrying that what you saw on the tablet may have been a mm or so IN or OUT from where the bullet would have hit the actual paper target...
You can travel to and spend your money at matches that have Electronic Targets.

Just enjoy your time on the range at whichever matches you choose to support with your attendance.

Some people may not even like hearing or reading about Electronic Targets.

That is the simplest to cure of all..
Those people can choose to not listen to people talking about them at matches or click on any threads discussing them.

Everyone can be happy...
Cheers

 

[243Mendoza]

Two of us did it in one session over multiple ranges as the further back you go so the finer the adjustments become in the algorithm hence the 1mm achieved repeatable. Random recordings after that is any thing out side the true error. You will see them when you compare the monitor to actuals. If you only ever use open face targets you will never know the differences that occur between open and closed systems. You will just wonder what went wrong with that shot or shots because the monitor is your eye. In steady conditions shooters adjust to the sighters and go all good. Drop offs and switches can show differences. The more correct the true error is the better the target performs..

Did you apply the change in H &W after shooting the group with the result of the egroup better matching the paper group?

 

[Bindi2]

Did you apply the change in H &W after shooting the group with the result of the egroup better matching the paper group?

Fire one shot measure that to see how it compared to the screen measurement x and Y, adjusted the H or W so the two came together , fired another for comparison. Repeated at the next range and the next till we were all the way back. The final range we were happy that the recording was as good as we could get it. Then a test shot at the shortest range on the way to pack up showed what looked like a pin hole match.

 

[243Mendoza]

Fire one shot measure that to see how it compared to the screen measurement x and Y, adjusted the H or W so the two came together , fired another for comparison. Repeated at the next range and the next till we were all the way back. The final range we were happy that the recording was as good as we could get it. Then a test shot at the shortest range on the way to pack up showed what looked like a pin hole match.

After this procedure is complete, did you shoot a group at 600 or more yards, measure each shot and compare to the etarget values and compute an average and standard deviation of the errors?

 

[Bindi2]

After this procedure is complete, did you shoot a group at 600 or more yards, measure each shot and compare to the etarget values and compute an average and standard deviation of the errors?

I didn't need to with my SMT. The error was too small and the same. I didn't need to know what the wind was doing to the bullet I only needed faith in the target.
The Kongsbergs are all shot tested with groups and compared. What you are looking for is repeatability regardless of what the error is. There maybe an odd error at times but they are usually in the outers of the target. Repeatability of the error not the AV or SD is what you want to look for. The same place ,the plot sheet over the actual shows this.

 

[Bindi2]

I have shot my smallest groups on this target mainly because I have a small 19mm white patch in the middle of the aiming mark. E Ts don't make mistakes they only record them unless the maths are wrong then all bets are off. Interference at the interface of physical to data is where it happens. Repeatability difference is acceptable and the shooter corrects for this without complaint or thinking about it.

 

[243Mendoza]

I didn't need to with my SMT. The error was too small and the same. I didn't need to know what the wind was doing to the bullet I only needed faith in the target.
The Kongsbergs are all shot tested with groups and compared. What you are looking for is repeatability regardless of what the error is. There maybe an odd error at times but they are usually in the outers of the target. Repeatability of the error not the AV or SD is what you want to look for. The same place ,the plot sheet over the actual shows this.

I do not agree. You need to define "repeatability of error". My definition of repeatability of error is that the AV and SD does not change significantly no matter the day, conditions or given unit of brand of system. Otherwise one cannot believe or trust in the result of a few shots and simple visual comparison of groups.

How do you calibrate your system? It seems that you are using H&W to calibrate.

 

[243Mendoza]

I didn't need to with my SMT. The error was too small and the same. I didn't need to know what the wind was doing to the bullet I only needed faith in the target....

So you are saying external mike systems are not suitable for ranges with wind?

 

[Bindi2]

repeatability of error is the error is always in a very similar place across the test or tests. AV or SD does not show or tell you where the error is only tells you have one. Closed sound chambers in working condition do not have wind issues. 5 mic open face do, 8 mics I don't know but should be better. The 5 mic I use shows the errors being more of a random type no pattern when the wind is up. You need a base level to start from the best result you can get from the target then test in different conditions to see what is actually happening.
Can you tell me any other way to calibrate for best base level of accuracy other than tweaking the H or W to get there.
When I am load developing the AV or SD is not a factor because I have faith in my targets recording. The wind will affect group size but I live with that knowing when testing should stop. When I shoot for wind reading learning I use other techniques or tricks which I know allow for the wind plus the error created on my target. I can only do this because I know the base error.

 

[243Mendoza]

...
Can you tell me any other way to calibrate for best base level of accuracy other than tweaking the H or W to get there. ...

Yes, there is a specific option to calibrate the system:
1)click on the gear wheel icon shown on the upper left and enter the admin password
2)take a shot or more
3)measure the 'x,y' locations of the shot on paper
4)click on the shot data shown on the right side bar
5)click on the 'calibrate' button
6)enter the 'x,y' values for that shot
7)repeat for all shots used for calibration