Chronograph velocity discrepancy

[Slide4949]

I have a Caldwell and a new CED M2 chronography.

 I put one in front of the other to double check velocity and have a average of 38 FPS difference.I swapped location of units and get the same readings.

I'm back 7-8' to fist unit and have light bars on both. Shooting inside. Shooting a 38 super open gun.That really makes a big difference on the power factor.

Which one is correct and why the big difference?

[Khaot1c]

Probably quality of internal components. The ol "you get what you pay for" is still true today. Just because things have gotten cheaper to manufacture doesn't mean they're better.

 

If it were me, I would go with the lower set of numbers.

 

 

Sent from my SM-N975U using Tapatalk

 

 

 

 

[zzt]

Both of those chronos are idiosyncratic.  The Caldwell is very sensitive to muzzle blast.  The CED likes the bullets to pass close above the ports.  I've used both, and now use neither.   I prefer the ProDigital Chrono.  It is more accurate, very forgiving and easy to set up and use.

 

Unless the bullet path is perfectly aligned with the long axis of the chrono, and parallel  to the plane of the ports, you will get erroneous readings.  They will be slower than actual.  The CED will read slower than the Caldwell simply because it measures over a 2' span rather than I.  That compounds the effect of an off axis bullet.  

 

CED M2s are what is used in chrono stations at USPSA matches.  So use the number yours provides when determining PF.

[gnoyesiv]

Our local ammo company uses the CED for there competition ammo since USPSA mainly uses it. and so far it has been pretty close to the ones ran at our state match and sectional.

[Hi-Power Jack]

3 hours ago, Slide4949 said:

 

I'm back 7-8' to first unit and have light bars on both.  

 

I like to position my Chrony 10 - 12 feet from the muzzle, so muzzle blast from my

9mm Major doesn't interfere with the readings.  I've had trouble at 7-8 feet.

[Sarge]

4 hours ago, Slide4949 said:

I have a Caldwell and a new CED M2 chronography.

 I put one in front of the other to double check velocity and have a average of 38 FPS difference.I swapped location of units and get the same readings.

I'm back 7-8' to fist unit and have light bars on both. Shooting inside. Shooting a 38 super open gun.That really makes a big difference on the power factor.

Which one is correct and why the big difference?

One thing for sure, you are too close. Set them at 10 & 12 feet.

  Secondly I have seen that much spread between two M2’s at a major. If you get chronoed enough you will even see one shot read higher on one chrono then next shot read higher on the other chrono. It’s not really an exact science. 

  This is why a seasoned chrono man told me he tests several M2’s when he buys them looking for consistency. He said screens, cables, power source etc all play a part in getting them to sync up at least close.

[Slide4949]

thanks Hi-Power Jack and Sarge, I will try moving back to 10 to 12'

[gm iprod]

Oehler 35P, simply the best there is. LabRadar #2, mainly because you can't put it down range. ProChrono Digital #3, everything else below them. You will also notice that the most expensive is the best.

I tested my Oehler, my ProChrono Digital, my brothers CED M2, and a LabRadar with the same ammunition at the same time. ProChrono and CED were slipped between the Oehler Sky Screens and all four were tested at the same time with the same factory ammo. The results were interesting to say the least. The M2 would show a slightly low velocity for the odd shot, which non of the others showed as being low.
If you are interested in down range performance, as in BC, then the LabRadar is the way to go. If you need velocity at a target some distance away then Oehler. The ProChrono is the easiest to use and would be the best value for money, even though it has some minor issues with sensitivity. the M2 has the advantage of having its brain away from the Screens so hitting the screen will not result in a new chrono. Oehler has the Largest Sky Screen and worked under nearly all conditions. LabRadar does not work without modifications if running subsonic and a suppressor. All in all. I prefer the Oehler, just a pain to set up. I sell more ProChrono and LabRadar. All except LabRadar have to be about 10ft (3M) to centre of Chronograsph Screens to work well and be relaible.

[Sarge]

9 minutes ago, gm iprod said:

Oehler 35P, simply the best there is. LabRadar #2, mainly because you can't put it down range. ProChrono Digital #3, everything else below them. You will also notice that the most expensive is the best.

I tested my Oehler, my ProChrono Digital, my brothers CED M2, and a LabRadar with the same ammunition at the same time. ProChrono and CED were slipped between the Oehler Sky Screens and all four were tested at the same time with the same factory ammo. The results were interesting to say the least. The M2 would show a slightly low velocity for the odd shot, which non of the others showed as being low.
If you are interested in down range performance, as in BC, then the LabRadar is the way to go. If you need velocity at a target some distance away then Oehler. The ProChrono is the easiest to use and would be the best value for money, even though it has some minor issues with sensitivity. the M2 has the advantage of having its brain away from the Screens so hitting the screen will not result in a new chrono. Oehler has the Largest Sky Screen and worked under nearly all conditions. LabRadar does not work without modifications if running subsonic and a suppressor. All in all. I prefer the Oehler, just a pain to set up. I sell more ProChrono and LabRadar. All except LabRadar have to be about 10ft (3M) to centre of Chronograsph Screens to work well and be relaible.

Great write up. You forgot to mention the Pro Chrono is only $100 or so while being nearly as good.

[gm iprod]

Sarge, Correct ProChrono PAL, is $100, Digital $125, New DLX is $135, need to get one of those for the shop to test. I think that could be the big seller through my shop. They are easier for regular guys to use and do everything they are likely to want. The DLX will be the one we will stock at the shop, for the sake of $10 or $25 you might as well buy that. 

For the more expert reloader the LabRadar and the Oehler are the way to go.

[warpspeed]

1 hour ago, gm iprod said:

Oehler 35P, simply the best there is. LabRadar #2, mainly because you can't put it down range. ProChrono Digital #3, everything else below them. You will also notice that the most expensive is the best.

I tested my Oehler, my ProChrono Digital, my brothers CED M2, and a LabRadar with the same ammunition at the same time. ProChrono and CED were slipped between the Oehler Sky Screens and all four were tested at the same time with the same factory ammo. The results were interesting to say the least. The M2 would show a slightly low velocity for the odd shot, which non of the others showed as being low.
If you are interested in down range performance, as in BC, then the LabRadar is the way to go. If you need velocity at a target some distance away then Oehler. The ProChrono is the easiest to use and would be the best value for money, even though it has some minor issues with sensitivity. the M2 has the advantage of having its brain away from the Screens so hitting the screen will not result in a new chrono. Oehler has the Largest Sky Screen and worked under nearly all conditions. LabRadar does not work without modifications if running subsonic and a suppressor. All in all. I prefer the Oehler, just a pain to set up. I sell more ProChrono and LabRadar. All except LabRadar have to be about 10ft (3M) to centre of Chronograsph Screens to work well and be relaible.

 

100% agree

 

I love my Oehler but it is a PITA to set up and take down so I have a ProChrono for the quick and dirty measuring.

 

If I used it on a regular basis I'd probably get a LabRadar but I haven't had either out this year so I can't justify that spend.

[kevin c]

It's great having an accurate, high quality  and consistent chrono that you can use to develope and test loads.

 

There's no way of knowing, though, what the match you spend your hard earned dollars and vacation time on is going to use at their chrono bay, and even if you did, it's still a different machine used under different conditions than those at home.

 

Given the above, I'd think it still sensible to give yourself an adequate PF cushion. 

[Chillywig]

On 10/15/2019 at 8:35 PM, gm iprod said:

Oehler 35P, simply the best there is. LabRadar #2, mainly because you can't put it down range. ProChrono Digital #3, everything else below them. You will also notice that the most expensive is the best.

I tested my Oehler, my ProChrono Digital, my brothers CED M2, and a LabRadar with the same ammunition at the same time. ProChrono and CED were slipped between the Oehler Sky Screens and all four were tested at the same time with the same factory ammo. The results were interesting to say the least. The M2 would show a slightly low velocity for the odd shot, which non of the others showed as being low.
If you are interested in down range performance, as in BC, then the LabRadar is the way to go. If you need velocity at a target some distance away then Oehler. The ProChrono is the easiest to use and would be the best value for money, even though it has some minor issues with sensitivity. the M2 has the advantage of having its brain away from the Screens so hitting the screen will not result in a new chrono. Oehler has the Largest Sky Screen and worked under nearly all conditions. LabRadar does not work without modifications if running subsonic and a suppressor. All in all. I prefer the Oehler, just a pain to set up. I sell more ProChrono and LabRadar. All except LabRadar have to be about 10ft (3M) to centre of Chronograsph Screens to work well and be relaible.

Ironically I read this post this morning and hit the range this eve and took the lab radar with. Was shooting 22lr match ammo that was all sub sonic and could not get the trigger to pick up the sound to record velocities. I tried adjusting the trigger level and it didn't work. Then I switched the trigger source from trigger to Doppler. Bingo it worked! It just keeps the radar on. I put the suppressor on and was able to record velocities shooting a sub sonic suppressed 22lr bolt gun. I love the lab radar but the app interface sucks! Prochrono app is much more user friendly

[Slide4949]

my question is if I go with the low reading on the CED, 170 PF but the caldwell is 176 PF and the 176 is right, then isn't that  getting too high and could damage gun ? 

[Sarge]

2 hours ago, Slide4949 said:

my question is if I go with the low reading on the CED, 170 PF but the caldwell is 176 PF and the 176 is right, then isn't that  getting too high and could damage gun ? 

176 in Open isn’t going to hurt the gun.

[Hi-Power Jack]

On 10/23/2019 at 8:43 AM, Slide4949 said:

  if I go with the low reading on the CED, 170 PF but the caldwell is 176 PF and the 176 is right, could damage gun ? 

 

I guess you've moved them back to 10 -12' and you are still getting a 38 FPS difference ?

[Slide4949]

yes I did move them back to 12' same results. I called CED and they said switch the start with the stop and try that, but it was a little worse.

They acted like no big deal just the way it is, too many possible reason why.

Edited October 24, 2019 by Slide4949

[Hi-Power Jack]

I'd protect myself by using the lower numbers, and then see how the chrono station 

calls it next match.   See if their chrono station favors one chrono or the other, or is

it right in the middle.

 

Can you check these against any other Chrono's ?

[Slide4949]

what brand chrono do you use Hi-power Jack?

[motosapiens]

If they consistently read differently, it doesn't matter that much, as long as it's consistent. As to which one is more correct, that does matter, and I would recommend trying some other ones, either borrow from a friend or go to a major match, etc...

 

In 6-7 years of doing major matches, and chrono-ing my own ammo before every match, I have found that my pro-chrono is generally the same or 1-2 pf lower than the match chrono, so I just rely on it and call it good. If I was generally 5 pf higher on mine than the match chrono, I would be loading to 173-175 instead of 168-170, but I admit it would make me feel funny.

[Slide4949]

I will check with some friends that have chrono and see what theirs read. 

 

[Slide4949]

ok, have new plan. Did some research and found that 9.3 gr of 3n38 in a Atlas Chaos with 1.23 oal produced a  170 PF.So with that I will use the chrono closes to that value.

[Hi-Power Jack]

15 minutes ago, Slide4949 said:

 9.3 gr of 3n38 in a Atlas Chaos with 1.23 oal produced a  170 PF.   I will use the chrono closest to that value.

 

Great in theory,  but YOUR gun may not get 170 PF with the same load.     

 

I've been using a Chrony (used to be $79) for the past dozen years, and

find it to be remarkably close at the major events where I've been chrono'd  (Is that a word?).

 

Just got a CED M2, but haven't opened the box yet.  

 

Based on your experience, I guess I'll run the two side by side also, and see what happens.

 

But, I've been happy with my Chrony - going to replace it because it's almost as old as I am.     

 

 

[Slide4949]

Let me know your results Hi-Power Jack. Anxious to find out.

[GregJ]

I've had a CED M2 for several years, but got tired of the unreliability, and error codes.  Even with a new sensor, and switching between start and stop, I have no confidence in it anymore.  I have sent it back to CED and they found nothing wrong.  I have since replaced it with a Caldwell G2. Price is reasonable (on sale at Midway, $229), super easy to set up, easy to use, etc.  Love the BT app.  So far, it seems to be in sync with rounds that I've had chrono'ed at a couple diff majors.