Chronograph

[scotty99]

I'd been using the Caldwell inverted type also for a couple of years. I'll say that the tripod it comes with is garbage. Flexy plastic 3-way camera head? Useless. I gave it away to Good Will and bought a decent SLIK tripod that collapses short enough to fit in the Caldwell case. I recommend that to anyone. I screw the chrony directly onto this tripod. No head needed. I love the BlueTooth ability.

But you know, I've gotten some really weird readings with my Caldwell. Made me not trust it. One day out in the bright sunny desert it was reading only 1800 FPS average from a 16" AR of mine, with ammo that was measuring at about 2800 or so in an 18"-barreled AR only a few minutes earlier. WTH? Not just one shot---two strings of five shots.

And on another day, same location and conditions, I was using it to measure speed on some 45auto hand-loads out of my 1911. Two strings of five shots each, first round it said the average was 1984 FPS! Second was 1846 FPS! I don't know if the chrono was multiplying by 2?

So I recently bought a MagnetoSpeed Sporter. Only used it once with one string of five shots. It worked though and the velocities seemed to be accurate. What I'd expect. Very compact piece of kit too. The only downside is no BlueTooth; the Caldwell has spoiled me on that point. And it does not save data. So you need to have a pad and pen handy to record the FPS, SD, ES.

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[Ki6vsm]

I have experienced some anomalies like you deacribed and everytime its been from muzzle flash. I just give it a little more distance and it gets consistent again. With magnum loads like huge 50AE I have to give it more distance, say 15'. But 10' works well for every thing else.

Could be in some cases. But broad daylight in the desert? And this was with the one rifle that actually did have a flash suppressor. And I don't think flash would be any kind of issue with a handgun in the same environment. I'll admit I was using the chrony inside of 10 feet from the muzzle. But still.

Another odd thing happened with it last year. When I was using my Grendel upper for the first time, firing factory Hornady Black ammo, and the chrony was telling me that my SD was 57, and the spread was 138. High of 2572. How could factory match ammo be that all-over-the-place, even in a brand new barrel?

Back to the tripod. This is what's so nice about a decent one. You can't go this low with the included model. And it'll as high as you need. Collapses small enough to fit in the Caldwell case. Here I had it set pretty close on this first outing with it, I'll admit. (Or I was still setting up?) But it worked fine that day. And this rifle has a bare muzzle:

[ocabj]

I'll admit I was using the chrony inside of 10 feet from the muzzle. But still.

The reason why you need to keep the chronograph at least 10 feet from the muzzle is to mitigate anomalies with the readings due to the muzzle blast and flash. As far as broad daylight, bright direct sunlight is actually detrimental to optical chronographs. Diffused light over the sensors is better.

[Dooder]

Daylight with the g2 doesn't matter. The sensor is underneath the upper deck pointing down. All light sensor chronos need distance and 10-15' is the standard. As stated before me its not just muzzle flash but blast as well. Plus if you input the distance of the chrono placement into the software it provides a calculated actual muzzle velocity. However within 15' is generally accepted muzzle velocity as the difference is going to be <5fps.

Sent from my moto g(7) power using Tapatalk

[Carcassonne]

I have Labradar and an Oehler 35P. I bought the Labradar because the 35P was a pain to set up, and it didn't work good in the forest. The light wasn't constant with the sun shining through the tree branches. The Lab Radar doesn't work with shotguns.

If you want a low cost easy to set up Chrono, try the Competition Electronics Chrono. You can probably get one on sale on Black Friday for $100.


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[Whiterabbit]

I like the magnetospeed best. Reliable, accurate, and fast to set up. Add the xfer cable and iphone app and its fast to transfer data to my laptop.

[kcstott]

Could be in some cases. But broad daylight in the desert? And this was with the one rifle that actually did have a flash suppressor. And I don't think flash would be any kind of issue with a handgun in the same environment. I'll admit I was using the chrony inside of 10 feet from the muzzle. But still.

Another odd thing happened with it last year. When I was using my Grendel upper for the first time, firing factory Hornady Black ammo, and the chrony was telling me that my SD was 57, and the spread was 138. High of 2572. How could factory match ammo be that all-over-the-place, even in a brand new barrel?

Back to the tripod. This is what's so nice about a decent one. You can't go this low with the included model. And it'll as high as you need. Collapses small enough to fit in the Caldwell case. Here I had it set pretty close on this first outing with it, I'll admit. (Or I was still setting up?) But it worked fine that day. And this rifle has a bare muzzle:

[Ki6vsm]

Thanks guys. All that's pretty encouraging, because I don't want to just toss it away. But I'd think the flashing/smoke blast would cause bad/no reads. Not a string of accurate velocities, then a couple of strings in a row of consistent but low-read (or too-high) velocities, followed later on by expected velocities again... under the same conditions give or take. From being "too close" I'd expect some randomness in the errors, not five reads out of five shots with tight SDs of just 6 - 20. So I don't understand the science of these errors, but oh well.

I did some reading and found this thread on ar15 dot com. Guy was having the same problem with some of his strings. 9mm pistol shooting at "2100 fps". All his other weapons/shots were normal. Said his chrony was 12 feet away. Got the same advice you guys are giving. Move it even farther away, watch out for bright sunlight, etc.

https://www.ar15.com/forums/armory/Way_too_fast_Chronograph_readings_/42-471441/

Next time I take it out there to the dez I'll set it up farther though and see how it behaves over a day of shooting. And I'll check it against the MagnetoSpeed since that's a super easy setup. Maybe at under 10' the chrony reads the shock wave or bow wave of the bullet loads + barrel combos and throws things off in a deceivingly consistent manner.

[Ki6vsm]

OP, I hope you don't mind and think i'm hijacking your thread. I figure this info might actually be helping with your decision.

FWIW, here is what the guy determined, see linked thread above. It was not the distance but the sunlight angle. He doesn't say what model of Caldwell he has. I assume the type with upward facing sensors since they're more common. But I will assume for now that it can affect the downward facing sensor type as well. I thought downward would make it less sensitive to sun, but perhaps not. Maybe I should run the lights on sunny days? Runs the battery down faster obviously, but at least it's rechargeable easy enough even out in the field.

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Was not a distance issue at all.
Angle of the sun was the cause.

Sun today was near identical to yesterday.
For the heck of it I set up the chrono in the exact same place and distance. Again Tula 115 spouts crazy 2100 FPS. Moved back to 21 feet 2593 FPS. So now I was worried...
Moved the chrono angle to the sun about 45 deg different. Bang Tula 1273 FPS as it should be.
All he other loads I shot today read correctly as well.

Still unsure of why the 300BLK loads would register correctly today and yesterday, where the 9mm wouldn't
The only speculative answer I can come up with is the shiny 9mm bullets and the 300BLK was powder coated black lead.

But either way the issue is fixed. Thank you everyone for your input.

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[Olderfart]

Check this briefly this morning but don't have a bunch of time today - this thread is Frigin Great -
Tons of info - Thank you
Keep it coming but I'm out of time today

[waveslayer]

Check this briefly this morning but don't have a bunch of time today - this thread is Frigin Great -
Tons of info - Thank you
Keep it coming but I'm out of time today

Best affordable Chrono hands down is the Labradar. I do extensive load development for myself and many others. I have a magneto speed as a random back up for out of state testing with suppressors, but the POI shift drives me nuts.

So go with the Labradar, they have a sale going on now. It is easy to use and has the best results. I use it for archery, a lot too. Don't get their tripod, buy one off Amazon, it works much better

My wife thinks I only have 3 guns

[Ki6vsm]

What do you think this guy's problem was with his Labradar? I'll admit, his title is a bit harsh:

https://www.youtube.com/watch?v=IySaDqv7OfU

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[Ki6vsm]

The reason why you need to keep the chronograph at least 10 feet from the muzzle is to mitigate anomalies with the readings due to the muzzle blast and flash. As far as broad daylight, bright direct sunlight is actually detrimental to optical chronographs. Diffused light over the sensors is better.

Meant to ask about this. Being as the sensors are in the top and point downward, how would you recommend diffusing the light below (in this case) the sensors? Maybe lay a piece of gray cardboard across the bottom of the triangle? Or rig some shade above the whole device?

[Dooder]

What do you think this guy's problem was with his Labradar? I'll admit, his title is a bit harsh:

https://www.youtube.com/watch?v=IySaDqv7OfU

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That's a terrible video. Not enough information provided to get an idea of what's happening. When the video popped up it indicated that I had watched and disliked that video already haaha. I got mine in early 2016 around the same time when the video posted so I must have stumbled on it when I was gathering information.

Sent from my moto g(7) power using Tapatalk

[micro911]

I used to have and used Ohler 35P. It was best one at the time. But, it was in 1990s.