Testing E Target Accuracy
- Thread starter Bindi2
- Start date
Keith Glasscock
Gold $$ Contributor
Considering the small percentage growth of the sport, what possible good does that concept do?
I'll save you from any hyperbolic statements on my part.
It simply isn't that hard to get right. The scientific method is my recommended method for quantifying, then developing mitigation for any issues that appear. It all starts with dedicated, objective, scientific testing.
Doug Beach
Silver $$ Contributor
We do play a game of chance. Skill is the larger variable, but chance plays into every shot.
Ned Ludd
Silver $$ Contributor
Keith has the right of it. If there are potential errors involved with the use of some technology, you do a rigorous and properly controlled series of experiments to define the error. Then you devise an approach to mitigate the error to whatever extent is possible.
This is real simple: if changes in wind across certain types of E-targets has the possibility of changing the acoustic center, (especially if it's by as much as 0.47", which is significant), then that is an issue that needs to examined experimentally. As has been mentioned previously, it is possible to move (offset) the target face (POA) as long as the E-target's acoustic center is calibrated with the target face in the desired position. That calibration is the only thing that establishes a defined link between the shooter's POA and where the target perceived the shot passed through the target. If shifting wind across the target face can move the acoustic center by as much as 0.47", that's a problem for a number of reasons. First off, the POA won't move in the wind, meaning the POA and acoustic center would no longer be properly calibrated. Second, it would not be equal across all targets as wind conditions are rarely ever identical across an entire range.
If the wind can alter the acoustic center of the target, an even more important question becomes how is ever possible to "trust" it, as was suggested above? Trust requires verification that a system works, meaning test must be carried out to validate a system is working as it is supposed to be. If no tests or verification are carried out, then trusting such a system is about as logical as believing in the Tooth Fairy. You can do that if you want, but I believe I would wait for appropriate test results before making any decision to "trust" the system.
This is real simple: if changes in wind across certain types of E-targets has the possibility of changing the acoustic center, (especially if it's by as much as 0.47", which is significant), then that is an issue that needs to examined experimentally. As has been mentioned previously, it is possible to move (offset) the target face (POA) as long as the E-target's acoustic center is calibrated with the target face in the desired position. That calibration is the only thing that establishes a defined link between the shooter's POA and where the target perceived the shot passed through the target. If shifting wind across the target face can move the acoustic center by as much as 0.47", that's a problem for a number of reasons. First off, the POA won't move in the wind, meaning the POA and acoustic center would no longer be properly calibrated. Second, it would not be equal across all targets as wind conditions are rarely ever identical across an entire range.
If the wind can alter the acoustic center of the target, an even more important question becomes how is ever possible to "trust" it, as was suggested above? Trust requires verification that a system works, meaning test must be carried out to validate a system is working as it is supposed to be. If no tests or verification are carried out, then trusting such a system is about as logical as believing in the Tooth Fairy. You can do that if you want, but I believe I would wait for appropriate test results before making any decision to "trust" the system.
A closed target shields the sensors from moving air. So long as there are no gaping holes in the front or rear the air inside will be still so there will be no "moving acoustic centre"). If the air is still there will be no "shifting acoustic centre" problem. You may have an acoustic versus visual centre offset, but it will be constant, which is better than moving randomly. There are a number of factors that can influence this centre offset.
With appropriate sound proofing around the frame, the sensors will be shielded from external sound. This ultimately prevents the so called "ghost" shot problem as sound has no easy path in from the outside. Bullets passing by that are really close (like within 1 foot of the frame) may be picked up depending on the sensitivity of the sensors. This can be beneficial. But shots close to or through the adjacent target will be suppressed. This is our experience.
There is another problem, or vulnerability, that more or less disappears with a closed target but I won't address it here.
We do have a pretty good understanding of the physics of acoustic targets now. We have a better understanding of some issues than other issues - we simply don't have the resources of NASA or similar organisations to properly delve into them all. But for our purposes what we do know is sufficient.
Closed targets are not without their problems however, but these are known, quantifiable, and manageable (after 10+ years of study/observation, and experimentation). They (like any target design) would all work great if people would just stop shooting holes in them! ;-)
Sensors [in a closed target] that are sensitive enough so they can work properly at long ranges can cause problems at short ranges (that results in a lot of energy at the target). Reducing the sensitivity so that they work properly at short ranges may render them unreliable at longer ranges (especially in hot and humid conditions, and at altitude). Electronically controlled sensor sensitivity (based on range/distance or other criteria) could be employed but who wants to pay for that? Maybe manually set sensitivity based on the range/distance being shot would be suitable? I guess what we all currently do is simply try to strike a happy compromise when it comes to sensor sensitivity. But it doesn't have to be this way, technically.
I don't think closed targets need to be expensive. Or heavy. I'm not sure where the line gets drawn between "expensive" and "not expensive" though.
With appropriate sound proofing around the frame, the sensors will be shielded from external sound. This ultimately prevents the so called "ghost" shot problem as sound has no easy path in from the outside. Bullets passing by that are really close (like within 1 foot of the frame) may be picked up depending on the sensitivity of the sensors. This can be beneficial. But shots close to or through the adjacent target will be suppressed. This is our experience.
There is another problem, or vulnerability, that more or less disappears with a closed target but I won't address it here.
We do have a pretty good understanding of the physics of acoustic targets now. We have a better understanding of some issues than other issues - we simply don't have the resources of NASA or similar organisations to properly delve into them all. But for our purposes what we do know is sufficient.
Closed targets are not without their problems however, but these are known, quantifiable, and manageable (after 10+ years of study/observation, and experimentation). They (like any target design) would all work great if people would just stop shooting holes in them! ;-)
Sensors [in a closed target] that are sensitive enough so they can work properly at long ranges can cause problems at short ranges (that results in a lot of energy at the target). Reducing the sensitivity so that they work properly at short ranges may render them unreliable at longer ranges (especially in hot and humid conditions, and at altitude). Electronically controlled sensor sensitivity (based on range/distance or other criteria) could be employed but who wants to pay for that? Maybe manually set sensitivity based on the range/distance being shot would be suitable? I guess what we all currently do is simply try to strike a happy compromise when it comes to sensor sensitivity. But it doesn't have to be this way, technically.
I don't think closed targets need to be expensive. Or heavy. I'm not sure where the line gets drawn between "expensive" and "not expensive" though.
Last edited:
Ned Ludd
Silver $$ Contributor
The problem is that there are lots of open target systems out there, and more are being purchased as we speak. So the notion of simply using a closed system will not completely address the issue, particularly if there is a significant price differential between the two types of target systems.
I resent your bolded implication above that I represent some commercial interests. I am not an owner, user or investor in or of any e target system. Nor am I in any position to proft from the sale of paper targets. I do own an entry level target camera system which has inadequate camera resolution, a problem I am attempting to resolve. By the way, i need to use reading glasses to see the ipad images; this causes me to dismount the rifle and put on reading glasses each time between shots. No such action is requred of me on paper targets with pullers, as I can see the shot marker in my scope or spotting scope, a simple head movement. This is something else which makes me less than eager to use e targets.
This thread contains enough information about the problems of sonic sensors that I have become convinced these products are in fact Gen 1.0, as I have stated elsewhere. Half an inch of error for each shot is unacceptable.
Someone post something about wrinkly paper. Please. Or, solve these obvious critical shortcomings and release a true Gen 2 product.
My bolded statement you quoted, Was not directed at you.
My apology that you interpreted it that way.
There will be those trying to sell high priced systems that will always work to cast doubt on their competition and some that will just plain never trust E targets period.
We all know who the salesmen are here. I thought it was obvious that statement wasn't directed at you.
As far as the rest of my post: if the shoe fits... well you know
As I said,
If you don't like or don't trust E targets. Support ranges that still use paper and pull pits.
E Targets aren't and never will be a good fit or accepted by everyone.
Was your camera system a Gen 1 or "True Gen 2" product?
Cheers,
George
Last edited:
----- end sdean quote ---------------
In my opinion that would be too much extra work for Match Directors and would take away from key benefits of E targets.
Again IMO, 99% of the ET bashers will always be bashers.
Even if / when they are no longer actively competition they will continue to bash from a comfy chair on the interweb...
Hopefully not every range in their areas go to ET's.
This way, If they like pulling pits and paper targets they can keep pulling pits and paper targets.
The rest of us will move on making the best of the next step in the evolution of the sport / game.[/QUOTE]
First and foremost those of us who sponsor matches find help to do this hard to get. If you are going to take all the centers and save them you are creating a lot of work. One of the benefits of ETs is being able to not go to the pits and we save the cost of centers and a place to store them. In all the testing I have personally done the amount of times that a shot scored differently on paper compared to the computer target is very minimal. I have tested and compared at 300, 600 and 1000 yards. I'm no expert, just a shooter and match sponsor. The ETs make our life a lot better and I don't feel that anybody suffers from a different score than what was scored on paper. When you suggest saving centers and targets you might as well go down to the pits and pull targets. The advantages of ETs far outweigh the disadvantages.
Earl Liebetrau
Earl338
Warren Dean
Team Savage F-TR
In my opinion that would be too much extra work for Match Directors and would take away from key benefits of E targets.
Again IMO, 99% of the ET bashers will always be bashers.
Even if / when they are no longer actively competition they will continue to bash from a comfy chair on the interweb...
Hopefully not every range in their areas go to ET's.
This way, If they like pulling pits and paper targets they can keep pulling pits and paper targets.
The rest of us will move on making the best of the next step in the evolution of the sport / game.
First and foremost those of us who sponsor matches find help to do this hard to get. If you are going to take all the centers and save them you are creating a lot of work. One of the benefits of ETs is being able to not go to the pits and we save the cost of centers and a place to store them. In all the testing I have personally done the amount of times that a shot scored differently on paper compared to the computer target is very minimal. I have tested and compared at 300, 600 and 1000 yards. I'm no expert, just a shooter and match sponsor. The ETs make our life a lot better and I don't feel that anybody suffers from a different score than what was scored on paper. When you suggest saving centers and targets you might as well go down to the pits and pull targets. The advantages of ETs far outweigh the disadvantages.
Well said, Earl
Rick, this is the type of test I was hoping to see, thanks for posting. I could not find an estimate of the wind value produced by the fan, that would be good to know. Also, it sounds like you did not remove the side panels from the Hex chamber box so the sensors may have not been seeing a true crosswind and the effective value of the wind may be difficult to calculate.
I would like to see a similar test of an open sensor system with a measurement of the wind velocity.
I am told that the picture of the flag in the lower left hand corner of the shot plot is representative of the wind so it looks like approximately 10 mph which seems like a good test.
Removing the side panels would not be possible as that provides structural integrity.
I'm thinking the purpose of the fan is to influence the pressure waves upon entry into the measuring device. This test accomplished that. I agree the actual wind speed from a digital tool would be great, but all the wind reading shooters know what the flags speak. For now anyhow.
As far as the same test on open faced targets. Yep. Vendors should provide that.
Here's the flag.VA_XTC_Shooter
Silver $$ Contributor
My bolded statement you quoted, Was not directed at you.
My apology that you interpreted it that way.
There will be those trying to sell high priced systems that will always work to cast doubt on their competition and some that will just plain never trust E targets period.
We all know who the salesmen are here. I thought it was obvious that statement wasn't directed at you.
As far as the rest of my post: if the shoe fits... well you know
As I said,
If you don't like or don't trust E targets. Support ranges that still use paper and pull pits.
E Targets aren't and never will be a good fit or accepted by everyone.
Was your camera system a Gen 1 or "True Gen 2" product?
Cheers,
George
George, the reverse could be said about those that convinced their club to purchase a pile of open etargets that were not yet signed off by CMP for matches, are not as accurate as closed systems, and want to attack others for pointing out the potential issues from open targets for match use instead of just practices as were designed.
Caveat emptor.
From the linked article: 9mm error. 9mm is .355 cal, more than the diameter of a .308 bullet. Can the manufacturer do the test with winds of variable speed and direction, such as are normally experienced at a real rifle match, and plot the results vs actual? Why did the forum proponents of these systems not alert us to these errors?
Does the wind never blow faster than 10mph?
So much for the oft-cited drawbacks of "wrinkly paper".
Is this the future of this sport? More importantly, should we accept this as acceptable and "just go with it", as some are telling us, or do we demand true results?
Would incorporating target face wind speed sensors and correction make these systems viable?
Is this the best we can do? Do you want to spend $thousands on equipment and more $thousands on time off and travel to shoot big matches on systems with errors greater than the diameter of your bullet?
"I want to shoot fast and not pull targets."
Unbelievable.
From the linked article: 9mm error. 9mm is .355 cal, more than the diameter of a .308 bullet. Can the manufacturer do the test with winds of variable speed and direction, such as are normally experienced at a real rifle match, and plot the results vs actual? Why did the forum proponents of these systems not alert us to these errors?
Does the wind never blow faster than 10mph?
So much for the oft-cited drawbacks of "wrinkly paper".
Is this the future of this sport? More importantly, should we accept this as acceptable and "just go with it", as some are telling us, or do we demand true results?
Would incorporating target face wind speed sensors and correction make these systems viable?
Is this the best we can do? Do you want to spend $thousands on equipment and more $thousands on time off and travel to shoot big matches on systems with errors greater than the diameter of your bullet?
"I want to shoot fast and not pull targets."
Unbelievable.
This test is interesting but confusing. The testers seem to imply to have shot 18 shots into a 1mm group at 400meters!!.
And they repeated this feat with wind on into the same holes as the previous group!!!
I am sure that i missed some detail in the test writeup since this accuracy is not possible?
I have reread this several times and it is not clear to me either, the following in particular:
"The example of the shot reported position without wind is shown in the left plot, and the reported position with the crosswind blowing, while the impact is in the same location as on the left picture, is shown in the right plot (note the wind indicators in the bottom left corners):"
Upgrades & Donations
This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.