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pjb45

CED M2 Reading Low Velocities

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My CED M2 Screen are a few years old, maybe four. 

In NM with the temperature about the same as in AZ for A2 my NM velocities were significantly low hence PF than when the ammo was Choron'd at A2.

NM was about 167 and AZ was 173.  This is pretty significant to me.

Previously, my NM velocities were very very close to those in AZ and NV (Area 2 and Nationals).

Now I have lost confidence in the CED.

I read (off a google search that older CED and produce lower velocities) there might be issues with older ones since it was on the internet it must be true-Right :wacko::surprise::roflol:

 

At A2 4.41 gr of VV 320 200gr Zero = 171pf, today 4.4 gr VV320 200 gr Zero = 160 pf.  This is crazy.

 

Any ideas?

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It might be because the sensors ended up moving over time. If the get tilted just one or two degrees inward or outwards it changes the distance that the bullet travels before the sensors "see it"  since optical sensors operate off a time/distance based calculation ANY change in alignment will greatly affect the accuracy.  I suggest the doppler radar based model called Labradar.  it cost a little more, but it will never get shot and it is extremely accurate in any light condition, etc.

Time to put a bullet through yours and end the misery.

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I thought I would update this post.

 

I purchased a better tripod.  The results were better. 

I had ammo from 4 matches that was chrono'd.  The steady, firm tripod resulted in results that were within 2% of the official chrono results. 

If you have seen the chono setup at A2 or Nationals, you know they use two sets of screens.  In my experience of watching the velocities it is pretty rare that both chronos have the same velocity. 

So I am pleased with my change to a better tripod--Amazon comes through again.

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The times I've had erratic velocity readings, were either because direct sun hitting the sensors, or more frequently, it's windy, and the screens are moving with the wind. So, a much sturdier tripod would help, as in your case.

And as far as the set-ups at the chrono tables with dual screens, you will always get different readings. Though they are together, one set of screens is still physically closer than the other, even if only by a few inches. Hence the difference.

Edited by Postal Bob

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4 different match chronos and your measurements were within 2%? That's great. How are you taking your measurements? Are you duplicating per the rule book? Taking the average of so many round? I'm really curious.  

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On 8/22/2017 at 9:20 PM, pjb45 said:

I thought I would update this post.

 

I purchased a better tripod.  The results were better. 

I had ammo from 4 matches that was chrono'd.  The steady, firm tripod resulted in results that were within 2% of the official chrono results. 

If you have seen the chono setup at A2 or Nationals, you know they use two sets of screens.  In my experience of watching the velocities it is pretty rare that both chronos have the same velocity. 

So I am pleased with my change to a better tripod--Amazon comes through again.

Both sets of screens should have different velocities as they are not at the same distance from the barrel.

What is interesting to me is when the farthest set of screens has the highest velocities.

 

Tom

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"I had ammo from 4 matches that was chrono'd.  The steady, firm tripod resulted in results that were within 2% of the official chrono results." 

 

PJB - how did you take your velocity measurements to determine you were within 2%?  Also what is the measured STD of your ammo?  

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Hiya, sorry for the delay.  Honestly, I don't remember and I did not download the data.  I shut down my Windows computer and just use my Macs now.

 

Also, I used an Oehler in-line with the CED and the results were more than 40 fps different. This was for more than 50 shots!

 

However, I did talk with the CED folks.  Nice people.  I am sending it back for a software update.

 

At Nationals, the chono measurement was 168+ while at home it was way below 165. 

 

My choro used to be spot on with the Nationals (OK, NV, UT and IL) chrono.  I still have ammo from those matches as my baseline.

 

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More:  I sent the Chrono back to get the software updated.  I took it to the range today with ammo from Nationals.  The Nationals chrono was 168 the updated software chrono was 167.5.

 

CED has nice service.

 

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That is good to know. I have a CED that is several years old and it is consistently low. Think I will be calling CED also. Thanks for the info. 

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