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Bfta Chrono


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#1 Piemanlarger

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Posted 12 August 2009 - 06:13 AM

Is the Bfta chrono not effected by direct sunlight?

I ask as when i checked my gun before lunch, it did 806 -811 (mozzie). Chrono was in shade under tent.

Before shooting lane 1 for the Pm session at Gp8 Sunday, my first shot read 835, the 2nd and 3rd 819fps so just in, given 827 is the limit = 822 Bfta. This time though there was direct sunlight on the Chrono.

There was no sign of any point of impact change (ie higher) from a gun running over on the zero range i had just left or the course

However, I heard lots of reports of high readings yesterday and know of one young sft shooter who was over and his Gun disqualified.

So, would direct sunlight on the chrono have effected readings sunday?




#2 rich

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Posted 12 August 2009 - 07:17 AM

There was a lot of campaigning a year or so ago to get the BFTA to adopt and apply consistent procedures to the chronographing process at all shoots as well as to have the kit regularly calibrated.

Our club chrono is a SKAN and we use that under cover AND we tape a piece of card over the exit to make sure no extraneous light comes in and form spurious shadows that fool it.

I was chatting last night to a member on here who took part on Sunday and he told me that his rifle was consistent at home between 805 and 810 with Mossies and he went through on Sunday at 807. Only one piece of "evidence" but it confirms what you have said, at one time the chrono was giving the kind of reading you would expect.

#3 alan-aitch

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Posted 12 August 2009 - 07:49 AM

I think it is affected by more than just light to be honest, failing batteries, water etc.....

I have always been in the pro chrono camp, my attitude being that if you were silly enough to run your gun close then you have to accept the consequences...........until Emley !!

Under the watchful eyes of a multi-time FT world champ, and the current (I think) UKAHFT champ (ie. people that now what they're at) the chrono put my gun a 16+ ft/lb a couple of times, then read it about right a couple of times, before throwing its hands up and refusing to read the next shooters gun at all confused.gif Having had some zero shift problems recently my gun, a P70, has spent a lot of time on the chrono and I know it's running consistently at around 775 fps with JSB's. I would not have been happy if I'd travelled all that way, paid for a room, and then been unjustly disqualified.

To be honest I still think we need to use a chrono but a consistent set up, ie. in the shade of a gazebo, is needed, along with calibrated kit. Having said that, the chrono at Emley was in the shade of a gazebo, it wasn't exactly blazing sunshine either............I have no answers rolleyes.gif

#4 rich

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Posted 12 August 2009 - 09:56 AM

What emerges as important from this, is that all shooters should be treated identically. It would in my view be unacceptable to give the benefit of the doubt to an established name because no-one can imagine his gun going over, yet issuing a DQ ticket to a lesser known competitor. Common sense no doubt suggested that your gun reading 16fpe must be an error of measurement.

I'm not suggesting this has happened, I think we just have to make sure that we guard against it. At another shoot, the chrono marshalls may not be so experienced.

#5 holly

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Posted 12 August 2009 - 05:38 PM

I dunno . it was quite cold at emley and my shutz went over at 755 . at nelson it went over at 777 . but it was pretty hot . so i reckon it was right ??? HOLLY

#6 robF

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Posted 12 August 2009 - 06:43 PM

Like Alan, i'm pro-chrono, and also like Alan i've seen it throw wild readings, and be fine the next.

I have suggested that the chrono readings are logged, so perhaps any trend in it's reading can be spotted. Perhaps it might be handy having a crombro to confirm a gun deemed warm...

I can imagine the BFTA committee pulling their hair out at another chrono thread though biggrin.gif

(ps, what's wrong with the BFTA forum? smile.gif)


#7 L-S-R

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Posted 12 August 2009 - 09:10 PM

Another possible is to have another chrono directly in front of or behind the PM-1 e.g a skan or something, both calibrated at same time and date. Have a rig set up so that they are both lined up.
The chrono in Wales at GP8 was under the shelter of trees inside a gizibo, so sunlight was not an issue. It was available to shooters before the shoot to check their guns so no excuses.
I would dare say that the high reading were from guns set up too close to the limit and being chronoed after spending up to 15 lanes in the baking hot 21 degrees direct sun, IMO.

#8 Piemanlarger

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Posted 12 August 2009 - 09:24 PM

QUOTE(robF @ Wed Aug 12 2009, 19:43) <{POST_SNAPBACK}>
I can imagine the BFTA committee pulling their hair out at another chrono thread though biggrin.gif

(ps, what's wrong with the BFTA forum? smile.gif)


No, well only one reply on bfta. Lets face it, most are on here or shooting the breeze!

As for the committee, to me its something that needs sorting. I know other Chronos would be effected by direct sunlight on them and given it started in the shade, i am thinking it should have been moved to stay in the shade.

I really dont think it gave anything like an accurate reading for my pm session testing.
Somthing that is going to put me off travelling up and down the country is a chrono that is incorrect / inconsistant. I'm alll for having it, but get it working properly or not at all.

#9 Piemanlarger

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Posted 12 August 2009 - 09:27 PM

QUOTE(L-S-R @ Wed Aug 12 2009, 22:10) <{POST_SNAPBACK}>
.
The chrono in Wales at GP8 was under the shelter of trees inside a gizibo, so sunlight was not an issue. It was available to shooters before the shoot to check their guns so no excuses.
I would dare say that the high reading were from guns set up too close to the limit and being chronoed after spending up to 15 lanes in the baking hot 21 degrees direct sun, IMO.


Sorry but your wrong on both of the above. The sun moves round and by 1.30pm the chromo was in sunlight, check out the pics.
My gun was chronoed technically before shooting any lanes in the afternoon as i started on lane 1. The gun had just done a dozen or so shots on the zero where nothing was going high and had then been left in the sahde awaiting the start of the gp.

#10 Guest_keyrigger_*

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Posted 12 August 2009 - 10:42 PM

Hello guys:

Many years ago, we were having extreme spreads from chronograph readings compared to those done at our home clubs. In most cases, the solution was to build a light box to place the chronograph in so that the lighting conditions would be constant from day to day. Just as happens with air guns, temperatures and humidity become the wild cards with the results. I have been the victim of wild swings in readings from day to day when I shot IPSC and this is no different. If you declared high power level and you were found to be at a lower one, you lost points or worse, if you declared low power level and you were found under that, you had no score. That would be your gun being disqualified. Once the box was established, the results were less likely to be way off your home readings. I do feel that given how important it is for the velocity to remain constant for elevation settings, I do not think that there is any concerted effort to claim lower readings and then be at the limit. Seems to be counter-productive for anyone to run their settings that close to the limit.

One thing that I do have is the manufacturer of the Shooting Chrony about a block and a half from my door. I have had my Chrony calibrated at least three times over the past 15 years and it has never varied. The last time, it read 1 fps faster than their computer driven calibration unit. We have then used my chronograph to calibrate others in my FT shooting group, so that they can make corrections if needed to their rifles, or know that they don't need to worry (like if their unit is reading slightly higher than the one I have. Mine is a very old analog (much like myself) unit and the owner/designer was very impressed that I have kept the unit that long and that the electronics have held up as well as they have. At least I can drop in anytime and pick up a new one right off the line. I am sure that is not the case with most owners of chronograph units.

#11 Jon

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Posted 13 August 2009 - 08:04 PM

Well Don your favourite chrono and various brand name ones i have personally seen them state +80ft/sec dependant upon the lighting.
Reckon theres something else as well that has an effect but need to do more tests.

What i find amasing is people are running more than 20 ft/sec faster than me and still passing.
Its not sunlight, it has thrown anomolies numerous times on cloudy days under a gazebo in woods, always has for 10 years.
The point being the chrono is being taken as gospel, i am with Alan on this one. Skans are as bad, i own one it wont register outdoors in any light. Wonder why you never see the safety camera vans out in dull or overcast weather! Theres more than 20% descrepancy in roadside laser signs with better electronics, just to wet the appetite.
Same goes when it throws up 300 ft/sec or whatever, known shooters inadvertantly adjust am, do the course then get copped because there has been a major change to the lighting pm.




#12 holly

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Posted 13 August 2009 - 08:06 PM

Don't forget that the chrono was right after lane 25 . which was in the sun and had been for a few lanes before . the guns getting hotter and of course the speed of the pellet going up . when these chronos first came out bainsy always placed a piece of cardboard in front and back of the chrono so the light was always the same . why not go back to that ??? HOLLY

#13 Kaytoom

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Posted 13 August 2009 - 08:07 PM

I was wondering about the chrono at Nelson . I had my gun checked about 8:30 , before I did the morning session , and I was down about 30 f/s on 2 different chrono readings the day before ???

I did'nt notice any POI change ??

I actually spoke to a few chaps about the chrono and we had a few opinions .

#14 Piemanlarger

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Posted 13 August 2009 - 09:00 PM

I could have sworn i posted this in the photos section, but cant see it!

So, this is the conditions that concern me as to the chronos use Sunday or other days for that. You shpould be able to see the front of the chrono in direct sunlight which i cant help but think will throw reading out by some degree.



#15 Guest_keyrigger_*

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Posted 13 August 2009 - 09:31 PM

Jon:

I have never seen such a large variation in readings from the chronograph I own (when I make sure that direct sunlight does NOT hit the sensors) from any air rifle/pistol I own. I think that an 80 fps variation could be an unusual occurance when you are taking readings from high powered rifles (over 2500 fps) and with the lighting swings from overcast to direct sun. From my recollection, most state an error rate of equal or less than .5%, and with the 2500 fps speed for an average high powered rifle, it would make a 12.5 fps variation within specs, and an 80 fps swing an unacceptable error. Maybe that must be taken into account more seriously and that the time may be at hand to change the specs for what is over and under. The 5 fps under ruling you use, may in fact be not enough to take electronic errors into account. I am NOT advocating increasing the 5 fps under ruling, but saying that it may be time to back off the tight tolerences used to dismiss shooters from a match at present. There will always be those that will push those limits to the extreme, and for those, pushing too far will still net the same result; removal from the match.

I am thinking of those competitors who normally have their rifles set at 40 fps below their ceiling limit, that then find themselves well over at a match (even though they had checked their rifle the day before and were right at spec). Does that mean that person has gone out and blatently tried to gain more speed from his rifle (and what does that do to his numbers?) or that he has been nicked by the error present in the chronograph, and other weather related factors? Doesn't that 40 fps also take into account the .5% error factor and leave a wide margin? Even setting a rifle at 20 fps lower is still setting it more than the .5% error in the chronographs. The real question may be, "Whose chronograph is the right one?". What do you do when someone gets a Combro checked and calibrated, then another has their Skan done, and the two of them read the same rifle differently? By which chrono do you send the person packing?

There is no question that there should be a ceiling limit in place so that the rifles stay as the rules state they must be set to. Is 5 fps over/under enough or should it, in fact, be even higher to take these errors in the chronographs into account. We are also adhering to WFTF rules for one of our divisions in Canda and need to make sure that the 12 fpe limit is not broken, so we too, are in this same situation. At least, most of the PCPs we have can be easily adjusted, since we normally do not have any anti-tamper placed on our 12+fpe rifles. I understand that it is not so easy to overcome with the most recent rifles made in England. I am only offering some help here with past experiences with chronograph troubles and I am not trying to exhonourate those that cheat.

Edited by keyrigger, 13 August 2009 - 09:33 PM.


#16 Jon

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Posted 14 August 2009 - 08:05 AM

Quite agree Don and have seen respectable chronos read as low as 300 ft/sec when actually doing 819 rain, sleet or shine all year round and not in natural light. Think you will find most chronos are +/-1%, could be wrong so at 800ft/sec it can throw any individual reading by 16ft/sec.

Harriers GP this year three shooters went through at 844, 844, 843 towards end of am session, so 40ft/sec under aint gonna solve the chrono error even 50 ft/sec wont. Hard rain at Millride as well, it still read 20+ ft/sec high.
Also the only time i have ever seen chrono read about right in close on 10 years was at Mad last year PM. It was pulled out of action for AM and by far not for the first time, simple task took 5 seconds to rectify.
As it stands we have to pass the BFTA chrono regardless of what reading it decides at that time, and the key point in their legislation.



#17 robF

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Posted 14 August 2009 - 11:31 AM

I suppose a shooter could always ask for the chrono to be moved...?

But it also seems to be some guns are problematic. One of my walthers is ok, the other one (without a stripper) is a bitch to chrono on many systems.

Inconsistent chrono readings leads to lack of faith in the device. The lack of chrono itself leads to lack of faith in people's rigs. Rock vs hard place... monkey tennis.

#18 rich

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Posted 14 August 2009 - 04:48 PM

In such circumstances you might as well play Russian roulette, when you have no idea what the result will be when you pull the trigger.

If the test process and test equipment cannot be made consistent, accurate and reliable then they may as well be dropped, regardless of how desirable a proper test may be.

#19 Kaytoom

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Posted 14 August 2009 - 04:56 PM

QUOTE(rich @ Fri Aug 14 2009, 17:48) <{POST_SNAPBACK}>
In such circumstances you might as well play Russian roulette, when you have no idea what the result will be when you pull the trigger.

If the test process and test equipment cannot be made consistent, accurate and reliable then they may as well be dropped, regardless of how desirable a proper test may be.


You are correct there , either a standard chrony used at each event inside a box , with calibration checked every time , or throw it away . It seems to be a lottery among the top shots as to where and when they are tested ..... confused.gif

#20 holly

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Posted 14 August 2009 - 09:25 PM

No no no no . a few years ago there was no chrono and the blokes who won were quite often the bloke who could get his gun up the furthest . you could HEAR it but you could not PROVE it . now you set your gun at the correct speed i set mine at 14 to 16 foot pounds . i win , you lose . now how long do you think you would travel the country doing comps when you know that you are being beaten by a cheat ? not long mates . this system is not foolproof but it is at the moment the best we have . i say again . i have been to a lot of GPs and i have never had a duff reading from the chrono . run your gun low and safe ??? HOLLY IF you want a system that cannot be affected by heat or cold . what is the matter with the ballistic pendulum .

#21 chrisJ

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Posted 15 August 2009 - 02:40 AM

The two PM1's that the BFTA use read 10fps different between them, I was with little Kev when he had the two cronos together at Newbury when setting up, He shot his rifle thru both within 1 min of each shot and I saw the variance and it was consistant differance between the two, Now my rifle is set on my home crono F1 to 805-08 fps using mozzies, If the BFTA use the fast crono I read 816-818fps ish and the other PM1 809fps ish never had a problem in 3 years passing the test, I believe that the fast crono was used in wales,If you run your gun close to the limit you could be deemed foul of the rules if so happens the fast crono is used, I saw a few run low 820 's at wales when the shooters swore blind they set there rifles to 810fps.
I am in favour of cronoing at GP's but the equipment does need to be consistant.

#22 rich

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Posted 15 August 2009 - 07:44 AM

So there you have it. Two official chronos reading differently. Why can't one of them be marked as "true" or "the one that we trust" and the other marked as "reads high" or "reads low"? If a proper calibration was done, each chrono would have its own certificate with a look-up table of two columns. You look up the indicated reading in the left hand column and read off what the true figure will be in the right hand column.

I'm in favour of eliminating cheating, hell's teeth I've had a few things to say about one or two individuals in my own region when I was comp sec, no names no pack drill, but I'm not at all in favour of DQing competitors on the basis of an unreliable test that can sometimes throw out random results.

If we all remember, a few years ago the rules were sudden death, you had one shot and one shot only over the chrono and that determined if you stayed or went. At least now it is more sensible, as long as one shot out of three attempts is OK then you can carry on.

#23 robF

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Posted 15 August 2009 - 10:12 AM

And all this is debated at the BFTA meetings a thread like this turns up... it's all been said before... but the BFTA is damned if they do, and damned if they don't.

#24 Piemanlarger

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Posted 15 August 2009 - 07:02 PM

QUOTE(chrisJ @ Sat Aug 15 2009, 03:40) <{POST_SNAPBACK}>
I am in favour of cronoing at GP's but the equipment does need to be consistant.



so am I. We set our guns up at tondu using the club chrono which was to the best of our knowlage running around 10 fps above bfta. Thus my gun is set to 810 which should be around 795 on bfta and previously at gp when working my gun has always been well in. It was only just before gp8 we found out there are two chrono in use, so we dont know which we "claibrated" ours by!

I started this thread as I believe the chrono being in direct sunlight sunday meant its ability to accuratly read the pellet was impared. Perhaps there should be a sign on the chrono saying avoid direct sunlight for test purposes?



#25 holly

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Posted 15 August 2009 - 08:16 PM

Yes pie man BUT this was caused by pilot error IE the gent in charge of the chrono should have been briefed and he should have had a piece of cardboard over each end of it to stop the light getting in , in the first place . lets get it straight . you do not get the best man for the job at club level . you get anybody who is silly enough to do it and get the hassel that goes with it . i say again . what about a ballistic pendulum . they used it in practical pistol . . you shoot at a weight on a pendulum of a given weight . it pushes a marker up the scale . as long as it does not go above a given height it is legal . does not matter about calibre . i t would be quite cheap and every club would be able to have one . would not matter about heat , cold or light . so you have an answer what do you say . ??? HOLLY

#26 Guest_sportsmatch_*

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Posted 15 August 2009 - 09:16 PM

Holly in practical pistol they used a chrono mainly a pact mk4 and they sometimes pulled the bullet to weight it also and what you are saying is back to front has you had to make a power factor 175 for major 125 for minor if you shot 174.99 you shot minor and if you made 124.99 you shoot for fun as your score would not count

Simon the chrono was under a tent under trees so would have been dappled light the photo you hosted was show with no person other than Pat. As the sun was behind the shooter light would have been resticted and Sunday was hotter than any days previous so your old NJR may have had a bit of heat stroke biggrin.gif

Gary

#27 RN10

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Posted 15 August 2009 - 09:45 PM

You never seem to get posts from people saying they know there chrono is right and use it to set the rifle power up but when they turn up at a GP they find the rifle is well under the BFTA one. I had the first PM1 in SEFTA which loads of people used and unless there was direct sun light on one set of sensors which was soon stopped by shielding it with some thing every one went by the readings and if they did have a problem over the BFTA chrono you alway got the same reading over my one when we were sorting it out. We even had 3 PM1s in a line so you got one reading off of one fired pellet and I think they where with in 8 fps which as % of 800 is nothing. And yes we did try the chrono's in differant orders with the same sort of spread .
As Holly said get rid of the chrono's and you are back in the bad old days.

#28 Piemanlarger

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Posted 16 August 2009 - 05:54 PM

QUOTE(sportsmatch @ Sat Aug 15 2009, 22:16) <{POST_SNAPBACK}>
Simon the chrono was under a tent under trees so would have been dappled light the photo you hosted was show with no person other than Pat. As the sun was behind the shooter light would have been resticted and Sunday was hotter than any days previous so your old NJR may have had a bit of heat stroke biggrin.gif

Gary


Sorry gary your wrong, the sun was at the front of the crono so the sun was infront of the chrono and thus shooter.

Look at the photo, it clearly shows the rear section of the chrono is shade while the front / sides are in direct sunlight, thats how it was before pm session.
My njr recorded 806 with no sun on the chrono, 835 with sun on it! Both times there was no shift in pellet strike so to I dont think i was running high at all.

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Posted 16 August 2009 - 06:21 PM

Simon I,m not wrong if the sun is behind the shooter it would be in the front of chrono and thus shielded by the shooter

Has you state the sun was in front of the shooter and in front of the chrono which is impossible no wonder you are having trouble with the chrono

Gary

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Posted 16 August 2009 - 06:46 PM

one thing that does vary the shot string results is the angle at which its fired through the chrono, if the angle changes so does the reading. I have found this on my skan which is in the attic with artifical light, postion the gun in a fixed point the shoot a string and have consistent reading then alter the angle and will see a consideably differance in velocity
Gary

did try to to edit above post but the edit function was throwing a wobbly




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