Accuracy of Electronic Targets

[dskogman]

I posted this before…
We have done extensive testing at Bayou Rifles and decided they are not accurate enough for our TSRA state matches. We do use them for club matches because everyone loves them and we get more shooters.

What we found is under relatively calm conditions accuracy is pretty good most of the time for good solid target frames. When the wind picks up they start to deteriorate. How much and how fast depends on the range topography, wind speed/direction, distance, among others. If you have target frames that move around and flex it’s worse.

The current NRA accuracy requirements are very restrictive making it impossible for an any open mike system to qualify except under ideal conditions at short range IMHO.

Should the rules be modified to make it easier to qualify an open mike system? Probably.
Should the manufactures improve their systems to make them more accurate and easier to find and resolve issues during a match? Absolutely.

 

[goodi]

Thankyou for all the positive responses.

As alluded to in the initial question my focus is on the suitability of ET's for benchrest application where precise group size measurement is the principle objective and score while also important is secondary.

For either 1000yd or 600yd BR I am trying to obtain actual information as to the comparison of the actual group size with the computer indicated group size and or any associated error.

Thankyou newbie shooter for your response and data.

Newbieshooter indicates measuring error of .009" .003" .011" .022" for his testing.

Would errors of this magnitude for group/score measurement be considered acceptable by LRBR benchrest organisations/ clubs/members etc ?

If not, has any decision been made on the required degree of ET measurement accuracy standards that must be met before they are considered acceptable for LRBR.

cheers

goodi

 

[F-CLassInfo]

With open mics being a trouble spot, I wonder if anyone has tried some sort of shroud around the outer half of the mic and put some sort of thin foam inside to reduce sound reflection. Might work.

Get after it! Ha

 

[F-CLassInfo]

I posted this before…
We have done extensive testing at Bayou Rifles and decided they are not accurate enough for our TSRA state matches. We do use them for club matches because everyone loves them and we get more shooters.

What we found is under relatively calm conditions accuracy is pretty good most of the time for good solid target frames. When the wind picks up they start to deteriorate. How much and how fast depends on the range topography, wind speed/direction, distance, among others. If you have target frames that move around and flex it’s worse.

The current NRA accuracy requirements are very restrictive making it impossible for an any open mike system to qualify except under ideal conditions at short range IMHO.

Should the rules be modified to make it easier to qualify an open mike system? Probably.
Should the manufactures improve their systems to make them more accurate and easier to find and resolve issues during a match? Absolutely.

NRA isn’t even following their rules on ET’s and matches. Not sure why they even have the requirements.

 

[Warren Dean]

Get after it! Ha

I am going to try it.

 

[INTJ]

Newbieshooter indicates measuring error of .009" .003" .011" .022" for his testing.

Would errors of this magnitude for group/score measurement be considered acceptable by LRBR benchrest organisations/ clubs/members etc ?

To determine the acceptable error, we need to see how much error we currently get in hand measured targets. When our buddy @GlennK shot his IBS HG (10-shot) 1000 yd record last summer, four scorers measured his target at the range. They were all within .010" of each other. They were: 2.698, 2.695, 2.688, 2.694.

So I would think the accuracy of an target would need to be inside .010".

 

[243Mendoza]

With open mics being a trouble spot, I wonder if anyone has tried some sort of shroud around the outer half of the mic and put some sort of thin foam inside to reduce sound reflection. Might work.

that would only work for shocks coming from the protected side of the sensor (for example, the left sensors would be protected from shocks coming from the left targets) but not from the unprotected side (shocks coming from the right side targets).

 

[jelenko]

that would only work for shocks coming from the protected side of the sensor (for example, the left sensors would be protected from shocks coming from the left targets) but not from the unprotected side (shocks coming from the right side targets).

Right. But it would increase the distance from the source.
Leads to maybe baffles on either side of each target.

 

[F Class John]

With open mics being a trouble spot, I wonder if anyone has tried some sort of shroud around the outer half of the mic and put some sort of thin foam inside to reduce sound reflection. Might work.

I know Doug has done his own testing over at Bayou but speaking for myself I can tell you because we shoot every week of the year with rain, snow or wind I had to try to find some kind of solution that met our needs most of the time. I tried everything from PVC to plastic cups to foam to levelour blinds and built probably 10 different contraptions to try to isolate wind and/or rain from the sensors. In the end for my particular situation I found that rotating the lower two sensors 90° (so they point down in the same orientation as the sensor above it ) solved 95% of my issues. I did a video Showing both rotated and non-rotated sensors as far as Accuracy goes and over multiple tests I really didn’t see much do degradation but admittedly we aren’t shooting national or even state level matches. It is not a fix-all and every range will have its own unique characteristics since literally every range is built differently with different berms, target carriers and other items in the way as you well know.
Keep in mind that the actual microphone or I should say both microphones on each sensor tower have to be completely unobstructed from receiving the sonic cone. A single raindrop and or a piece of tape on them and they won’t function correctly.

just my 2 cents…

 

[243Mendoza]

Right. But it would increase the distance from the source.
Leads to maybe baffles on either side of each target.

True. It would be worth a test to see any difference before and after the mod. But I suspect it will not make a difference since the shocks can travel a long distance relative to target locations.

 

[rardoin]

My results with the Shotmarker system on less than rigid carriers/frames, fairly rigid frames and a very rigid frame mirror @dskogman ’s findings. First off if there is flex in the frame the alignment of the microphones will be off and significant error results in a degradation of accuracy that is undesirable for registered F-Class matches. Obviously benchrest would be a non starter. If there is a significant crosswind there will be up to .5” at 965yds (confirmed in a 7-11 mph @ 0800 recorded with a Kestrel). The 965 yd frame I would describe as fairly rigid and is hung on a purpose built very rigid carrier. I have also seen the same lateral error in similar crosswinds at 300yds on a very rigid smaller frame. I am fine with using them for monthly f-class matches but not for registered state/regional/national championships unless all the frames were very rigid and identical (ie- purpose built non-sliding rigid carriers/frames where no twist could occur and all competitors targets reacted the same to wind).
Bottom line is that I would not want an etarget recording groups if I shot BR. For verification of the number of shots on target I think it would be great. A well maintained system is very reliable on capturing shots. The maintenance is simply replacing the easily and cheaply sourced audio cables cables when they fail.

 

[Ringostar]

From the beginning of this thread. They’re not looking to measure br groups from the target sensors. Just verify how many shots came onto that target. Also as people have talked about target carrier movement. The sensors on the Silver mountain targets at Lodi, are not mounted on the target frames. They’re all solid mounted on poles along the pit wall. They don’t flex with the wind blowing on the target itself.

 

[goodi]

As a point of explanation, the motivation for this inquiry was to obtain opinions and feedback on the current suitability of adapting ET's for the purpose of holding LRBR matches.

Specifically, to compare the level of group accuracy/score measurement presently being obtained from ET's and compare these results to the existing manual measuring tolerances that are considered acceptable when using paper targets.

 

[rardoin]

From the beginning of this thread. They’re not looking to measure br groups from the target sensors. Just verify how many shots came onto that target. Also as people have talked about target carrier movement. The sensors on the Silver mountain targets at Lodi, are not mounted on the target frames. They’re all solid mounted on poles along the pit wall. They don’t flex with the wind blowing on the target itself.

That method of mounting should greatly reduce any error. That is a novel approach.

@Ringostar - this thread is precisely about accuracy of measured groups. This is a spinoff of a prior thread about using them in place of a moving backer.

 

[ChrisNZ]

.. The sensors on the Silver mountain targets at Lodi, are not mounted on the target frames. They’re all solid mounted on poles along the pit wall. They don’t flex with the wind blowing on the target itself.

Most ET systems in NZ are SMT with a few SM around. As above, the mic mounting bases are permanently fixed to solid frames and the targets themselves slot into these frames. The targets themselves are effectively immobilized in their carrier frames so no movement/alignment issues there.

We recently fully rebuilt our four 3/600yd local target frames so I was able to check the mounting setout.

You can see the drums full of shredded car tyres that stop/collect the bullets. The range is on a farm so we need to avoid lead contamination.

 

[Dos XX]

They aren't accurate enough for BR. They aren't accurate enough for F Class, either

 

[Medic505]

They aren't accurate enough for BR. They aren't accurate enough for F Class, either

But, But, I can sit on my ass and eat cheese and crackers and not have to go to the pits and possibly break a sweat and, and........

 

[Ned Ludd]

They aren't accurate enough for BR. They aren't accurate enough for F Class, either

And yet here we are, with e-targets being used in F-Class matches at ranges across the country. Myself and numerous other opponents of the use of e-targets in F-Class tried for some time to get others to consider exactly what might happen before their actual implementation. We were largely ignored. NOW people are becoming concerned with their accuracy/precision when their use is already widespread? Sorry. It's a bit too late. Kinda seems like passing a Bill first so you can read what's in it later (N. Pelosi LOL). Heck, even I caved and bought myself a ShotMarker. Given the cost to replace them, e-targets are here to stay. We can only hope that the manufacturers of e-targets will continue to research and find way to improve their accuracy/precision with input from users, because the NRA doesn't seem to be too concerned about it.

As has already been noted in this thread, it seems like e-targets might be a reasonable substitute for LR BR matches, solely as a method to count shots, but not for use in measuring group size. However, it should be noted that some e-targets will occasionally fail to record a shot for reasons that are unclear. I'm not talking about crossfires/misses, but shots that clearly hit the target and weren't recorded. In fairness, the occurrence [rate] seems to pretty rare, but I have seen it happen more than once. Nonetheless, it would be a concern for the BR shooters in the event they decided to adopt e-targets solely for the purpose of counting shots.

 

[Dos XX]

However, it should be noted that some e-targets will occasionally fail to record a shot for reasons that are unclear. I'm not talking about crossfires/misses, but shots that clearly hit the target and weren't recorded. In fairness, the occurrence [rate] seems to pretty rare, but I have seen it happen more than once.

Not that rare in my experience.

I also have an e target. They are a useful tool.

 

[F-CLassInfo]

But, But, I can sit on my ass and eat cheese and crackers and not have to go to the pits and possibly break a sweat and, and........

Your gettin grumpy in your old age lol