How accurate is your chronograph?

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GeneT said:
I suspect that their "calibration" involves something like artificially stimulating the sensors in sequence with a light source, or something along those lines. Perhaps just adjusting their prescaled clock freq. It's almost certainly automated. I guarantee that for their price and volume they aren't firing projectiles over them and a calibration chrono. An assumption, to be sure, but I'm pretty confident in it. It would be interesting to know definitively.

GsT
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Overall it appears they're well thought through - i'd have pretty high confidence in their process & methodology.

Radars... there's been some really good talk on other forums from guys that have worked with radar for 40+ years, they basically giggle when radar Chrony's come up.
 
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BABz58 said:
No idea. Never realized it was a problem for others. This is literally the first post I’ve seen with accuracy concerns with a Chronograph.

But then I didn’t buy mine to check its accuracy.
I got it to give me numbers to work with.
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Who does a heap of back to back comparisons in all conditions - it'd be expensive & most YT channels are somewhat "shills" for specific brands.

I've literally calibrated 1000's of chronographs & my OCD has made it an interesting adventure.
Things like how its mounted or fixed, even vibrations are INCREDIBLY influential on the results, unless you're doing LOADS & LOADS of testing you wont pick these things up.

Its also just a LOAD of marketing - put some decimals in the results & people assume they're more accurate & those decimals arent just spitting out the same numbers over & over & over again ;)
 
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My chronograph numbers will vary with changes in light, temperature, altitude and distance away from the first sensor.

Even if my chronograph gives me exact numbers those numbers will vary with a whole bunch of external variables.

I don't care if there's a small drop or gain between checks as long as the spread is low. Data collected on one afternoon may not match others. If I see a steady decline between checks then I know things are slowing down. But as long as the spread is low and it will drop them close together the exact velocity isn't that important to me. I just aim a little higher.

I've always plotted the arc of the pellet by shooting targets at various ranges rather than calculating the curve using a ballistics program. When I have plugged my data into the ballistics program it was pretty close to my field data. I think the variation was more about the numbers for pellet BC than chrono error.
 
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I have found it to be useful when buying a new AG to clean the barrel, fire about 100 pellets, clean again (tells you a lot about barrel condition if you don't have a borescope), and then do shot strings over a chrono with a couple of pellets you are not likely to run out of. Ten years down the road, this can be very useful if performance gets strange.
 
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My $30 chrono reads 30fps low compared to my Caldwell. The Caldwell reads 40fps low compared to my Garmin. After buying the Garmin, I dropped the pellet velocity and the groups at 50yards and 100yards improved significantly. Pellets and slugs have typical velocity ranges for accuracy. Poor chrono accuracy just makes find that range much more difficult because you can't use the typical velocity ranges as a starting point. This is more problematic at long ranges where many factors effect performance. With poor chrono accuracy you can't eliminate velocity when trying to systematically find the root cause of poor accuracy.
 
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Really ? The only instance i can think of where a crony would have to be less than +/_10FPS (or even 20FPS) accurate would be in a low powered gun (HW30 ) shooting at distances greater than the design or maybe shooting over 100? or 200 yards . Assuming the average springer is tuned @ 12 to 14 FPE 700FPS
would an animal think "Wait I'm not dead that guy was 25 FPS slower that his crony indicated " HAHAHa
 
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dens228 said:
Hmmm, good question. The only way to know is to get another one and compare the two. But then if they are different how do I know which one is right. I guess I'd have to buy a third to compare..........
No, I'll just assume the one I have is close enough.
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This is why I’ve always had more than one chronograph. Before radars, I still always had two and they read differently. But when one starts to line up with what you’re seeing real world from what you have plugged into your calculator, I stick with what that chronograph is telling me. Important to some and not to others. Just depends on how far you’re shooting and what your gun is capable of.
 
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beerthief said:
Really ? The only instance i can think of where a crony would have to be less than +/_10FPS (or even 20FPS) accurate would be in a low powered gun (HW30 ) shooting at distances greater than the design or maybe shooting over 100? or 200 yards . Assuming the average springer is tuned @ 12 to 14 FPE 700FPS
would an animal think "Wait I'm not dead that guy was 25 FPS slower that his crony indicated " HAHAHa
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Most bench shooters demand the best accuracy on the market & well below that... however its mostly around shot to shot consistency, which is typically better than the absolute measurement of speed.
 
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I would agree, for most of us, as long as it serves it's purpose, then it's good enough. Consistency is the rule there.
If i'm feeling a bit ocd, i keep a cheap Chinese chrono for confirmation. Just today i did some chrono work with a different reg in my Impact, was getting some unexpectedly high velocities on my Garmin, so i pulled out the China Chony and it was less than 2 fps different.
I do believe that current light chronos are plenty accurate and radars are slightly more accurate from all my research.
 
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NateChrony said:
Most bench shooters demand the best accuracy on the market & well below that... however its mostly around shot to shot consistency, which is typically better than the absolute measurement of speed.
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I agree with this if you’re shooting at one known distance. But if you are shooting at various distances all the time there is no way velocities that are off are going to let you calculate what you need to accurately.
 
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Vetmx said:
I agree with this if you’re shooting at one known distance. But if you are shooting at various distances all the time there is no way velocities that are off are going to let you calculate what you need to accurately.
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Dont disagree at all.
If you're a casual shooter - you probably dont need this at all.

The only other use case for non-benchers/serious would be equipment tuning & diagnosing - how consistent is your platform & can you get any more out of it. If 10fps variance is enough - then 100% that'll do pig, that'll do.
 
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I now own just three chronographs.
GARMIN - Taiwan
P.A.C.T - Texas with Chinese components (like my iPad, iPhone, computer, TV, truck parts, scopes, binoculars, etc., etc, etc.)
I used chronographs extensively when loading for powder burners, especially when loading for my son who was a champion 3 gun shooter. They have to meet or exceed certain power levels.
I have only one PCP (Prod).
All of my other airguns are factory standard springers, pumpers, CO2 and SSP.
I adjusted the PRod settings to obtain 15fpe with 16 shots.
I may have to return the PRod to the factory power of 12fpe for use in Pistol FT if I decide to try that again and I will verify the speed and energy.
I see no real need to have to use either of the chronographs again unless someone at the range needs to check their speed.
 
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NateChrony said:
Most bench shooters demand the best accuracy on the market & well below that... however its mostly around shot to shot consistency, which is typically better than the absolute measurement of speed.
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Shot to shot variance does not effect accuracy independent of velocity. As average velocity decreases the same variance with cause larger groups size.
 
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Raider03 said:
Shot to shot variance does not effect accuracy independent of velocity. As average velocity decreases the same variance with cause larger groups size.
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Sorry - maybe I didnt put it well.

There's 2 things with Chronograph accuracy:
- How close the result is to the actual speed of the pellet
- How consistent the results are at a given speed (cant think of a better word when talking uncertainty)

Example:
- Pellet speeds: 1000, 998, 999, 1002, 1001
- Chrono reading: 1010, 1008, 1009, 1012, 1011

So its reading 10fps high off actual pellet speed, but every reading is exactly 10fps off - the consistency is there.
A chronograph like this will be ok for testing, as shot to shot its "accurate".
 
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