Electronic target scoring methodology

[Tim Conrad]

Not ISSF. 50ft in U.S. I understand some folks in Europe shoot 15 meter smallbore indoors, which is close to 50 ft. (15.24 meters) Almost all of our clubs shoot paper, and scoring i.t.'s on soft paper is a bit of a chore.

[iawan]

Dear David,

Seems like u have recently attended EST Course. Congrats.

Can you send me few guideline for preparations for EST Course and sample questions for preparation. I have heard very few qualify EST Exam. Is this correct

This sounds like a question from the ISSF EST Judges course I was on a couple of weeks ago.

To score a 10.00 the centre of the pellet must be no more than 2.50mm from the centre of the target (the radius of the ten plus the radius of the pellet). The decimal scoring rings are therefore 0.25mm apart, which gives:-

Up to 0.25 = 10.9
Up to 0.50 = 10.8
Up to 0.75 = 10.7
Up to 1.00 = 10.6
Up to 1.25 = 10.5
Up to 1.50 = 10.4
Up to 1.75 = 10.3
Up to 2.00 = 10.2
Up to 2.25 = 10.1
Up to 2.50 = 10.0

Your method of calculating the distance from the x and y coordinates is correct.

edit note: The above should obviously read "Up to and including....."

[ruig]

Secret ISSF document with lookup tables :-)

[David Levene]

Can you send me few guideline for preparations for EST Course and sample questions for preparation. I have heard very few qualify EST Exam. Is this correct

The main advice I can give for taking the EST course is to make sure you are happy with using the Pythagoras Theory for dealing with right angled triangles.: The square on the hypotenuse is equal to the sum of the squares on the other two sides.

If you can apply that and have reasonably good eyesight then you shouldn't have too many problems.

On the course I took (a couple of years ago now) nearly everybody passed. There is a higher level pass (from memory 89%) which only 3 of us passed.

It's a good course. Who's running the one you're going on.

[iawan]

Can you send me few guideline for preparations for EST Course and sample questions for preparation. I have heard very few qualify EST Exam. Is this correct

The main advice I can give for taking the EST course is to make sure you are happy with using the Pythagoras Theory for dealing with right angled triangles.: The square on the hypotenuse is equal to the sum of the squares on the other two sides.

If you can apply that and have reasonably good eyesight then you shouldn't have too many problems.

On the course I took (a couple of years ago now) nearly everybody passed. There is a higher level pass (from memory 89%) which only 3 of us passed.

It's a good course. Who's running the one you're going on.

Dear David,

Thanks for the reply.

Mr Derek will be instructor.

Pythagoras Theory for dealing with right angled triangles is not a problem. I can do it. How much should be speed.


2nd Do it need to verbally know ISSF rules for deduction of penalties in malfunctions. Frankly speaking, i know most of rules but still i need to consult book for some decisions.

3rd, do they allow to use ISSF regulations book and EST Manual during test or no.



Regards

[David Levene]

Derek Ivy is probably the most knowledgeable person there is about EST.

If he follows his standard format then you will be able to use the manual and the rule book.

Just enjoy the course. It is extremely easy to learn when the instructor is passionate about the subject.

[john_almighty]

a stupid but curious question:
How would you know if your neighbour shot your target, say from accident.

[David Levene]

a stupid but curious question:
How would you know if your neighbour shot your target, say from accident.

Not a stupid question at all.

In practical terms there is little difference between paper and electronic targets, especially at 10m.

If you see an unexplained shot hole appear on your monitor then you would need to follow the procedures laid down in 6.11.8 of the rules. If everyone denies cross shooting then it's just as difficult to handle on both target systems (at 10m). The only advantage on electronics is if a subsequent examination of the log print shows 2 shots hitting the target within a few seconds of each other. If that is less than the reloading time then the shots must have come from different guns.

The position is much easier at 25m and 50m provided that backing/witness sheets and backing targets are used. Triangulation will show which firing point shots have come from. That is the same though with paper targets if backing targets are used.

[Spencer]

6.11.8.3 If a shooter receives a confirmed cross-fire shot and it is impossible to determine which shot is his, he must be credited with the value of the highest undetermined shot.

A lot of people overlook the determine which shot is his bit and it is often (not always) determined by inspecting the shot holes. It can be surprising how different shot holes can be from shooter to shooter on a line.

[Mike Carter]

Did anyone ever create the translation table? Or, an excel formula that would take the X value and Y value, perform the math and generate the score value. One score as the raw decimal value and the other as the integer and center shot or not.

Mike

[Azmodan]

Did anyone ever create the translation table? Or, an excel formula that would take the X value and Y value, perform the math and generate the score value. One score as the raw decimal value and the other as the integer and center shot or not.

Mike

this is the formula i came up with for freETarget:

score = 10.9999 - ((9.9/((outer_ring/2) + (caliber/2))) * shot_radius)

works pretty well for air pistol and air rifle

[spektr]

Gentlemen.
Im missing something.
How so you assure that the target image is repeating on the holders acoustic center point. Since it is replaceable, wouldnt changes in scoring occur based on the displacement of the Target Image relative to the mixrophone array???

[Mike Carter]

The center is the center regardless of where the center of the aiming mask is.
That is what sight adjusting knobs are for on the rear sight.
It is not physically possible to position the center of the target mask exactly to the center of the electronics. I would venture each time the mask is replaced the center moves ever so slightly.

[Green_Canoe]

The center is the center regardless of where the center of the aiming mask is.
That is what sight adjusting knobs are for on the rear sight.
It is not physically possible to position the center of the target mask exactly to the center of the electronics. I would venture each time the mask is replaced the center moves ever so slightly.

Not having ever shot at an electronic target before, if I understand you correctly when I leave home to shoot a match with electronic targets thinking I'm perfectly sighted in, I'm not. So those sighters are critical and I have to shoot enough to make sure my group is centered to the electronic target and not the black ink on the paper? That's not comforting to this shooter who majors in inconsistency.

[spektr]

The center is the center regardless of where the center of the aiming mask is.
That is what sight adjusting knobs are for on the rear sight.
It is not physically possible to position the center of the target mask exactly to the center of the electronics. I would venture each time the mask is replaced the center moves ever so slightly.

And this is my issue...... Im a retired tool engineer. Indexing components together was my day job. We shoot at an aiming point defined by the replacable aiming mask(target). We do not shoot at the point defined by the acoustic sensor hiding behind the aiming because we cannot see it. There must be linkage between the target centroid and the acoustic sensor centeoid or you will be introducing an error of random direction and magnatude with each mask change..... That gives me pause

[Mike Carter]

Consider this. Silver Mountain and Shot Marker systems utilize a large black paper circle for the aim point. The center is calibrated by hand with a measuring tape.
The Sius, Megalink, and Kongsberg target masks are a sheet of paper with hole cut in the center the size of the aiming black. The background being either the pellet or bullet catcher, or a black strip of paper are what turns it black. The projectile passes through the paper untouched except in the instance of a score value of 3, 2, 1, or 0. The sensors measuring the x y plot of the projectile is accurate to 5 decimal points of a millimeter.
Sius, Megalink and Kongsberg are designed to be shot with aperture sights. Can they be shot with a scoped rifle? Yes, and I have done so. But I didn't aim at the center of the black circle. I drew a dot on the paper to give myself an aim point. Adjusted the scope so my shots would register center shots. IE passing through the center of the sensors. Again, the center is the center and the score is dependent on the where the projectile passes through those sensors.
Mounting the target mask so the center of the hole is aligned with the exact center of the sensors is not relevant, unless the rifle is mounted in a rigid system that is incapable of being moved. But consider this, the target mask is typically held in place for by 4 dowels at each corner affixed by pre-punched holes in the paper. Kruger makes these targets for Sius. There manufacturing process has a certain tolerance but it is not absolute zero. Or even close. We reuse targets when switching from 10 meter to 50'. The holes are enlarged after they are removed. It probably changes the center point, but not the accuracy of the target system. So a given rifle that was zeroed one day, then the mask is changed and the same rifle with the same shooter shoots on that target on a different day, it would not be uncommon for that zero to be off by a scoring ring at 10 meters. Requiring a sight adjustment to zero the group.

[Tim S]

So essentially any variation from the target mask is no different to accommodating wind?

[Azmodan]

The center is the center regardless of where the center of the aiming mask is.
That is what sight adjusting knobs are for on the rear sight.
It is not physically possible to position the center of the target mask exactly to the center of the electronics. I would venture each time the mask is replaced the center moves ever so slightly.

And this is my issue...... Im a retired tool engineer. Indexing components together was my day job. We shoot at an aiming point defined by the replacable aiming mask(target). We do not shoot at the point defined by the acoustic sensor hiding behind the aiming because we cannot see it. There must be linkage between the target centroid and the acoustic sensor centeoid or you will be introducing an error of random direction and magnatude with each mask change..... That gives me pause

freETarget, like SIUS and other ESTs, have the sensors and the target/mask holder fixed to the same position. that means that the paper target/mask is always installed in the same position relative to the sensors, plus or minus a very small amount. That amount is probably less than 0.5mm for SIUS. for freETarget, it is as much as the builder of the target housing is capable (with the 3D printed target face, i would say it's within 1mm).

[Mike Carter]

Another interesting note I discovered at the range.
A brand new box of Kruger target masks for the Sius 10 Meter Air Rifle Target.
With a stack of 7 or 8 pulled from the box I looked to see how well the 4 alignment holes and the target hole lined up. I would say perfectly.
Then I took one target from the stack, flipped it around and laid it back on the stack.
Low an behold, the target hole was offset from the target behind it by at least 3mm.

So there is a front, and a back. They are not marked, nor does it matter. But from one shooting session to the next, if the target mask is replaced, your particular zero could very well move left or right 3mm depending whether the replacement mask was oriented the same or not.

[Hemmers]

As others have said, for the mainstream manufacturers like Sius, Meyton & Megalink, the "aiming mark" is actually just a hole in the mask. There's no physical target that you could go back and compare against the monitor or printout (unless you fit a witness sheet, but that's not a target with rings on and is mostly useful for detecting cross-shots). Although it may feel "untidy", it literally doesn't matter whether the target's calibration is actually in the centre of that hole or off to one side - you can't see where your shots are falling.

Obviously it is desirable that the calibration be fairly close to centre simply so that you don't have shots tearing up one edge of the mask - especially for 10metre where you can see holes in the mask with the naked eye.

Coming to it as a predominantly outdoor shooter, any re-zeroing you may have to do against the target's calibration is usually hidden by adjusting for wind anyway. It is perhaps more obvious for air shooters, particularly air-pistol shooters who don't tend to adjust their sights much. I recall someone on this very forum replying to a question about adjusting pistol sights who said that if you were grouping away from the bull then it must be because something changed in your grip and you should figure out what that was. If your sights are zeroed from training then it must be you! This is perhaps technically correct (if you can know for sure the sights haven't been knocked or shifted in transit), but the majority of the other posters simply weighed in "if it's a consistent group then shift your sights for heaven's sake, don't throw the match". Don't be scared of your sights.

This willingness to tweak your sights is perhaps more important with EST, but has always been important as you travel to different ranges with different lighting, etc.


On the topic of cross-shots, the latest Megalinks can self-detect cross-shots as they have two of the optical measurement planes which means the computer can detect when a shot passes at an oblique angle. That's effectively all the witness/backer sheet did - provide a second measurement plane - but you had to wait until the end of a match to get your witness sheet back whereas the Megalinks can now do it automatically and even estimate where the shot came from (left/right, how many lanes up or down!).

There must be linkage between the target centroid and the acoustic sensor centeoid or you will be introducing an error of random direction and magnatude with each mask change..... That gives me pause

You won't be changing masks mid-match (though you may move targets if you have a failure - in which case insist on fresh sighters and not just continuing your match shots). On a reasonably well designed target, whatever shift there might be will be very small and adjusted for when zeroing. It certainly feels "untidy" for the zero not to be in the middle, but in practical terms it simply doesn't matter. We should treat the aiming mark and the target as two different things - if you've ever tried shooting at "eccentric" targets where the 10-ring is not in the centre of the black aiming mark you'll have found it makes absolutely no difference to your shooting (once you have adjusted your zero). On the NSRA novelty targets the offset is different on each mark, but on an EST any offset from the mask would be the same and consistent until the mask is changed.

As Mike Carter says, if you want to use a scoped rifle on those types of EST then you have to set up a separate aiming mark entirely because there's nothing to aim at in the centre of an EST. Your shots will absolutely not be going where your scope is pointing!