Cheating at the Chrono

[Xfactor]

That would bring atmospheric conditions and bullet ballistic coefficient into the equation big time... probably more complicated to get it "right" than the current process.

All the conditions are brought into the equation currently, being that the bullets are fired out of the gun in varying conditions. You don't need 100 yards difference in the targets.

No more so than they are under the current system. We're not measuring theoretical velocity, we're measuring actual velocity. I think this idea has a lot of merit.

Atmospheric conditions affecting powder burn rate, etc., would be the same... but testing velocity over long distance (as opposed to 10ft from the muzzle) would bring into play all the atmospheric affects on the flight of the bullet - not to mention the varying inherent BCs of all the bullets from different competitors - which will profoundly affect the "actual" velocity. Adding distance to the test makes it much harder to standardize in any workable fashion than the current chrono process.

Edited June 3, 2009 by Xfactor

[dqshooter]

Chronograph? Power factor?

What would John Wayne do?

Meet a sidekick in a cute manner, argue with a woman with whom he's had a past relationship, punch an annoying guy in the nose, throw someone in jail, kiss the woman awkwardly and shoot a bunch of men......

....then he'd report to chrono --- Not! :roflol:

.....unless we're talking about Hatari or Hellfighters, of course --- then the plot's a little different..... :D

Hell: the duke would walk up to the chrono shoot and smack the operator just for questioning that he would ever stoop that low as to try to pull some crap like that. He would of course always make major.

[big_kahuna]

IMO the discussion of chrono variability, precision, accuracy etc is an interesting academic exercise.

In practical application, load hot (fast) enough to have confidence at any reasonable chrono you encounter. If that means 175-180 PF at your "home chrono" so be it.

I went minor... once. Lesson learned. Never again if I can help it.

[ima45dv8]

It is also my understanding that if Friday shooters chrono and lets say the chrono is suspect.....5 shooters go minor that never do and question the chrono......Then on Saturday the same issue arrises for the first squad then the Range Master determines that in fact there IS issues with the chrono and tosses it......Is is correct, that according to the rules, that everyone that chronoed prior to the chrono being tossed their power STANDS???

Appendix C2, item #20:

20. If the Range Master determines that variances or malfunctions make further

testing unreliable or impossible, the power factors of competitors who have

been successfully tested will stand. The power factors declared by all competitors

who have not been tested will be accepted without challenge, subject

to any applicable Division requirements.

[kevin c]

The concept that poppers (all poppers in a match) could be set to fall at an exact power factor would be impossible to execute on the range. Uneven ground, soft ground, and popper design/contruction are variables which would prevent setting poppers at such a precise point.

Imagine trying to set a popper so that it falls to a 125PF load hit at the bottom of the ball, yet does not fall if that same shot hits just below the ball. I don't think so.

YMMV

Understood, George. But all I'm pointing out is that the way poppers used to be set (at least out my way) made sure that competitors couldn't go too close to the minor PF floor (as established by the chrono ammo) without penalty. Granted it isn't exact, but it was practical test of having "full power" ammo.

Catfish's idea is much the same, though would use some innovative technology. Might be expensive, and, once the plate became known, if there were only one or two, they could still be gamed around on that stage.

Popppers calibrated to minor PF, Ring and Paint major PF poppers mixed into many/most stages would be an unavoidable barrier to sub PF floor ammo.

Just food for thought - thankee all for the indulgence

[boo radley]

I'm all for a 10% random sample chrono procedure. Obviously people might complain about being singled out, so have an EZWS option "pick 10% 20%.. random shooters". I think that would do far more to deter the actual cheaters without interfering with the well-meaning shooters that might or might not be just over or under the line depending on the chrono...

Why did that rule change? According to Linda, that's the way things *were*. I'd really like this -- sort of like an airport TSA approach, and randomly selected for screening, but better, 'cause not everyone has to take off his or her shoes.

Those few that DO get selected - chrono and maybe an equipment check; mag gauge or whatever. I'm not saying The Rules aren't sufficient reason enough, to do the right thing, but hell - with all the money, work, time and thought going into tweaking mags, equipment position, etc, etc,....it would be nice if the occasional check validated the effort. :/

[Skizeks]

OK I read all the posts and the only thing I know now is what I new before,

Shooters don't agree on anything!!

When I go to a match, big or small, and I go to chrono.

What I want is to be at major for this match.

Like when you ask a dog what time it is.

It is always Now. Don't matter what it was at home!

Duane

[mactiger]

My dog wants a full size copy of your avatar, Duane.

Troy

[North]

Given that 165 PF plus 4 % is a 171.6 PF, could we not just as easily argue that loading to 172 is cutting it to close? After all USPSA provided a standard.....

For minor that would be 131.....

But...but...

+1

Speaking from a pure Metrology standpoint, that dog just don't hunt. USPSA has stated the chrono needs to be accurate to +/-4%. In the USAF we use a 4 : 1 standard; Basically you need to have a standard four times more accurate than the measurement your making. If we apply that standard to what we do, the acceptable range of our major power factor should be 138.6 to 191.4 FPS.

If we really want to have a 165.000 minimum power factor floor for "Major", then we need to have a "target" power factor of 197.

[buddy_fuentes]

Speaking from a pure Metrology standpoint, that dog just don't hunt. USPSA has stated the chrono needs to be accurate to +/-4%. In the USAF we use a 4 : 1 standard; Basically you need to have a standard four times more accurate than the measurement your making. If we apply that standard to what we do, the acceptable range of our major power factor should be 138.6 to 191.4 FPS.

If we really want to have a 165.000 minimum power factor floor for "Major", then we need to have a "target" power factor of 197.

??? ???

Edited June 4, 2009 by ima45dv8

[XRe]

If we really want to have a 165.000 minimum power factor floor for "Major", then we need to have a "target" power factor of 197.

??? ???

He's right.... but luckily, in practice, its not that sensitive... and generally, nobody dies if we fail in our sport (vs. USAF)

[Jim Norman]

OK, We all seem to admit that the Chrono is allowed to be "off" by 4% approximately. Then arises a couple questions. If I Chrono at exactly 165PF, am I really there? I could be only 158.65PF and still be shooting Major. I could also be minored shooting a PF of 171.8!

Should we have a PF Floor that is set as it is at 165, BUT allow the Chrono Accuracy as deviation, in other words, we would assume that IF you shot a 158.65 that you COULD be at the very low end of the Chrono variance and as such actually had a PF of 165?

Or just to be on the safe side do we all now need to load to a PF of 172? in which case we COULD actually be loading to 178.9 if the Chrono we use is reading at the opposite end of the variance?

Me, I tend to load up just over 170 for major and usually in the middle 130's for minor. I always felt that cuttiong it close was not woth the 4.5 cents worth of powder saved for the match.

Jim

[XRe]

OK, We all seem to admit that the Chrono is allowed to be "off" by 4% approximately. Then arises a couple questions. If I Chrono at exactly 165PF, am I really there? I could be only 158.65PF and still be shooting Major. I could also be minored shooting a PF of 171.8!

Yes, this is possible. Luckily, it doesn't seem to ever work out that way, but the theoretical possibility is there...

Should we have a PF Floor that is set as it is at 165, BUT allow the Chrono Accuracy as deviation, in other words, we would assume that IF you shot a 158.65 that you COULD be at the very low end of the Chrono variance and as such actually had a PF of 165?

I think you find great resistance to this - you would find people trying to load to 160 PF, and claim chrono variance. The best thing, in this case, is to set a limit (165) and stick to it.

Or just to be on the safe side do we all now need to load to a PF of 172? in which case we COULD actually be loading to 178.9 if the Chrono we use is reading at the opposite end of the variance?

Yep. But again, luckily we seem to not generally bump up against the tolerances in that fashion... Somehow, the "black magic" seems to mostly work...

Me, I tend to load up just over 170 for major and usually in the middle 130's for minor. I always felt that cuttiong it close was not woth the 4.5 cents worth of powder saved for the match.

I'm loading up to 175, lately Gun runs real nice at that point, though...

[Xfactor]

OK, We all seem to admit that the Chrono is allowed to be "off" by 4% approximately...

Should we have a PF Floor that is set as it is at 165, BUT allow the Chrono Accuracy as deviation, in other words, we would assume that IF you shot a 158.65 that you COULD be at the very low end of the Chrono variance and as such actually had a PF of 165?

I think you find great resistance to this - you would find people trying to load to 160 PF, and claim chrono variance. The best thing, in this case, is to set a limit (165) and stick to it.

I've been thinking about this too, and I agree with XRe that if the leeway is there, folks will just load to the low end of the 4% margin on their home chrono, and hope for a "cooperative" match chrono reading. We'll end up basically lowering the power floor to 158.6, and still have shooters scratching their heads when they make minor

Or just to be on the safe side do we all now need to load to a PF of 172? in which case we COULD actually be loading to 178.9 if the Chrono we use is reading at the opposite end of the variance?

Maybe it's best to just think like 172 is the new PF, with a +/- 4% tolerance which would allow for a reading down to 165.1. As much as a +4% variation (resulting in a match chrono PF reading of 178.9) would be a bummer, I'd rather that than be scored as minor. Short of someone coming up with a system that is much more consistently accurate, I think we're just stuck with loading to ~ 172.

Edited June 4, 2009 by Xfactor

[larry cazes]

Short of someone coming up with a system that is much more consistently accurate, I think we're just stuck with loading to ~ 172.

Yes folks...I think we have a winner!

In a previous career as a design engineer I spent years characterising various phototransitor/emitter pairs used in telemetry devices to read electric, gas, and water meters over a cellular network so transducer/sensor technology is a specialty of mine. I believe that the technology that we use today is a good trade off of cost vs. accuracy vs. repeatability for this application. We could spend a huge amount of time and money developing better chrono devices and require that everyone use them at level II and higher matches, which would cost us all money, or we could just load to a reasonable margin and let it go. 172pf minimum in ALL of my open and limited guns has worked for me for years. At matches where I have had to chrono or have worked that setup myself, I tend to see the same folks bitchin about the results consistently. These are the folks who load to 167-168 and then wonder why they went minor.

[dqshooter]

I understand that there is a diviation tolerance or allowance for USPSA. It seems to me that the folks I have seen go minor are one of two catagories:

1. Power factor is very close and it could just be an ops (small %)or;

2. Way off and you were hoping not to have to chrono and lets face it "you got Caught".

[Al Capizzo]

It is not that hard to build a "chrono coffin", even if it is just cardboard. According to the Nationals chrono crew it isn't unusual to lose as much as 100 f/s

when chrono'ing in the box verses a chrono open to the sky. I believe this is what bites a lot of people. If we chronograph our ammo at home and think we've got a good margin at 172 pf, then lose 100 ft/second at a match it can be very disagreeable. Ask me how I know.

[shred]

The problem with 'just add a bit of powder' is you do that.. and then again six months later, then again for Nationals... and sooner or later you're blowing stuff up.

We desperately need to account for significant figures in the chrono result and do the rounding properly. If that math is too hard (why I think I learned to round in grade school, but you never know), let 164.whatever slide and we'd be at least better off than we are now.

[BritinUSA]

I agree and that's why I think we need a margin of error for PF. My experience is that there is too much variability. I have been to numerous matches where people have noticed significant variations in their loads. Either we come up with a accurate way of calibrating these things at the range or we start giving the benefit of the doubt to the shooter.

I simply do not understand why we have to overload the guns to 172-175PF to make a 165PF at Nationals.

I wonder how many shooters would tolerate a 2-4% discrepancy with shot-timers ?

[buddy_fuentes]

Before Area 6 I tested load after load using two chronographs. I was trying to stay in the 170 to 175 power factor area. I had two loads I liked and one shot a tad more accurate. At area 6 it went across the screens at 185.6 PF! I didn't notice the difference in recoil or muzzle rise. Videos of me shooting looked like I was shooting minor...

Move to the Mississippi Classic, same scenario testing. Decided to change load (reduced) by one tenth of a grain. Tested and it was shooting around 170 to 173...across the screens at the Classic, 166. something! Now I'm shocked for sure. Are my friends and I testing wrong or is there something else going on?

I don't feel the difference in the two loads in recoil or see it on video. I'm loading safe at 175 on my chronograph. If I want to shoot minor, I'll use a nine.

Buddy

[Franklin D Wolverton]

I think really the only way to coming close to "solving" this problem is for USPSA to come up with a required chrono set-up (kinda like the classifiers... here's what you MUST have, and how it MUST be set up).

This would include one make and model of chrono...

Don't really see this happening though...

Frank

[XRe]

The problem with 'just add a bit of powder' is you do that.. and then again six months later, then again for Nationals... and sooner or later you're blowing stuff up.

Not with N105, you ain't!!!

[BritinUSA]

Move to the Mississippi Classic, same scenario testing. Decided to change load (reduced) by one tenth of a grain. Tested and it was shooting around 170 to 173...across the screens at the Classic, 166. something! Now I'm shocked for sure. Are my friends and I testing wrong or is there something else going on?

That's exactly the sort of thing I am talking about. The variation that exists from one chrono to another or from the same chrono in different locations. There is no consistency. You basically have two choices. Overload the rounds to make sure you are above 165 or play the lottery; In my opinion the chrono is not a measurement device, it is a gateway to another dimension where the laws of physics only partially apply.

There has to be a better way.

[ihatepickles]

We desperately need to account for significant figures in the chrono result and do the rounding properly.

Yes, this has been an issue for me since I first read the rulebook. I've always been worried that the answer to "why don't we use correct metrology?" would be "too hard for the chrono guys to get right". If that's the only thing standing in the way of having a fair chrono outcome, I feel sad that we're lowering the bar.

I wonder how many shooters would tolerate a 2-4% discrepancy with shot-timers ?

I think we're already tolerating this... Run 3 timers and watch the difference in the splits. We place a lot of credence in timers that report accuracy to .01 seconds but are not repeatable to .05 seconds even within the same brand/model timer.

Don't even get me started on the high hitfactor calculations with 6 or more significant figures that are derived from 3 significant figures. It ain't right...

[Xfactor]

I think really the only way to coming close to "solving" this problem is for USPSA to come up with a required chrono set-up (kinda like the classifiers... here's what you MUST have, and how it MUST be set up).

This would include one make and model of chrono...

+1