Chronographs...

[Poper]

About 20 years ago, I broke down and succumbed to the urge to buy a chronograph. I bought the blue Shooting Chrony.
Using the Chrony, I was mildly frustrated with my load development projects because what seemed to me to be too wide of extreme spreads and higher (than I expected) standard deviation. I was getting 1" 5-round groups and better with my 6.5x55, .270, .30-06, .308 , .222, .243 etc. - and the ES was usually in the 30-40 fps and SD was rarely less than 18.
A couple years ago I bought a LabRadar to replace the Chrony. No, I didn't shoot the Chrony! I thought about it, but I didn't do it.
I have only used the LabRadar a couple times. (I had been tasked with the care of my elderly mother and she passed away2/8/21. I was then tasked with settling her estate. FINALLY completed THAT nightmare scenario early May this year.) So now, when work and other obligations permit, I can get to the range, again.
Old habits die hard, of course, and my routine of load development is to shoot for groups and when a load is deemed good enough for consistent small groups, THEN run 'em over the Chrony. - Just because it is a nuisance to set up and tear down. So I have been developing loads for my new-build 6mm Creedmoor and a new (NOS) Browning A-Bolt III in .308 Winchester. Last Tuesday I shot 4 - ten-round strings and chronographed them using the LabRadar. To much to my surprise I was getting ES's in the low to mid 20's and better with SD's in the 10.35 and less! One string with the 6mm CM had an ES of a bit over 9 an SD of just over 3!!
Now I'm thinking the Chrony might have been lying to me over all these years and my loads were actually performing better than it was reporting to me....
So, I'm gonna see if I can catch the Chrony in the act. The next time I go to the range, I am going to shoot over both chronographs at the same time and compare the read-outs.

BTW, I really like the LabRadar once I got used to using it. Set-up is relatively simple. A good tripod is a must and I use the bottom tube of a retractable pen taped to the top and situated in the sighting groove with the small end pointed toward the target for alignment. Plus, at the end of the session, the data card makes inputting the data into my computer a snap.

I'm thinking I'm gonna be spending more time at the range. Just don't nobody tell the Better Half!

 

[rfwobbly]

Thoughts...
• Sorry for your loss. I was executor for my mother and you're right... even though my mother had already divided up all the household goods, getting all the finances worked out took forever.

• I use SD and ES numbers to give me a feel for how accurate my ammo manufacturing process is. With pistol ammo I like to see SD numbers below 15. With some brands of powder I can even get single digit. But I do not think that low SD numbers equate to accuracy or smaller groups. There are still a lot of other places for error to creep in, like bullet-to-barrel fit and crosswinds at long distances.

• I do not use a LabRadar, but I designed military radar for 3 different companies and understand how it works. I do not think you're going to see exactly matching numbers between the 2 types of chronos. The Chrony is highly dependent upon the quality and direction of the light source, and the proximity to the muzzle. I may be wrong and either way, I'd love to see your results.

Regards

 

[FROGO207]

My understanding is that a regular crony uses a bullet shadow to time the speed. The Labradar uses a setup similar to a metal detector to sense the bullet passing. It is not affected by shadows or muzzle blast so I feel it will be more accurate due to that alone. I do not own a Labradar either yet. I do await your findings though.

 

[longdayjake]

There is a new one out that is phenominal. RMR was actually looking at making something very similar and then the new one was released that does 99% of what RMR was going to do. So basically we put a bunch of time and money into something that will just look like a copy of what someone else has already done. Basically, it's a labradar that's been modernized and improved in about every single way. It's the FX airguns ballistics lab. Downside is it's $1000 or more from dealers but it will read velocities past 4000 FPS and out to 300 yards and it calculates the BC for you. It won't yet do G7 BC even though it says it does, but that can be calculated pretty easy using the G1 BC.

 

[jmorris]

Now I'm thinking the Chrony might have been lying to me over all these years and my loads were actually performing better than it was reporting to me....
So, I'm gonna see if I can catch the Chrony in the act. The next time I go to the range, I am going to shoot over both chronographs at the same time and compare the read-outs.

It’s kind of, ”a man with one watch always knows what time it is a man with two is never sure.”, thing.

There are a number of variables that can cause inaccuracies but I too test new ones against the others I have, when I add one.


I found the Shotmarker is very close to my proChrono.

 

[hdwhit]

I bought a Red Shooting Chrony in the early 1990's. I took it to "accurate enough" until the mal-adjusted sights on a friend's gun hit one of the skyscreen supports. I replaced the supports with shish-kabob skewers and the scyscreens with the stippled plastic from a gallon milk jug. The result was quite surprising as the velocities became more uniform.

I have no doubt that a LabRadar will provide greater accuracy, but for my purposes, a shadow detection device has been adequate.

Look forward to seeing your results.

 

[Barmcd]

I've seen comparison tests of lab radar and prochrono and they were both surprisingly consistent. Where there were discrepancies, the discrepancies tracked with both machines. If the prochrono produced a different number, it consistently produced that difference. Pretty good for an inexpensive device.

 

[Frulk]

Blue Chrony owner/driver here with a brand new Red one still in the box under the reloading bench should it ever be needed. Probably safe to say that most owners think cloudy weather has an impact on readings. So does set up proximity to muzzle. I've had some issues early on where I was getting a lot of error or wacky readings. I attributed that to unburned powder and inconsistent set up distances from muzzle.

Overall, once I read the manual in detail and started to set it up consistently at the same distance it (the readings/data) settled down. Didn't hurt either that its now sitting on a $300+ carbon fiber tripod. I consider the Chrony to be the price leader in value and ease of use/transport. I use it primarily to evaluate my pistol loads and over the counter rifle ammo. I'm satisfied in that situation of the quality of the data it provides.

 

[JerkyFreak]

Well, if you just need to know the consistency of your load, any repeatable chrony will do provided you use it the same way each time.

If you want to predict trajectories you need something accurate. Labradar, FX chriny or Magnetospeed.

 

[lordpaxman]

Plus, at the end of the session, the data card makes inputting the data into my computer a snap.

They do have an app that makes it somewhat easier to control and move data. The SD card is an easy method too. I find the Labradar very helpful especially in capturing V when doing load work up with an OCW method.
Regarding your ES and SDs, you’d need to verify your older calibers with your newer Chrono. You can have very good precision at closer ranges with not so great SDs.

I do not think you're going to see exactly matching numbers between the 2 types of chronos.

At a recent match they had 3 Labradar’s stacked, none of them registered the same velocity and it varied by single to double digits. I’ve seen this quite a few times.

 

[jmorris]

At a recent match they had 3 Labradar’s stacked, none of them registered the same velocity and it varied by single to double digits. I’ve seen this quite a few times.

I have seen it many, many, times. almost every time I set more than one up. That said a difference of 1 fps when measuring something moving ~3200 fps is 0.03125% difference and they just don’t have that accuracy; however, thats not something they try and hide.

Labradar’s manual claims a +/- 3.2fps accuracy for an object moving 3280 fps. So anything between 3283-3276 fps would be acceptable to them for an object actually going 3280. 6.4fps range, if you noted double digit discrepancie, they are optimistic in their accuracy evaluation.



There was a good paper of the subject I came across years ago that documented even shot placement inside the acceptable “window“ of regular chronographs, that showed the importance of shooting through the same spot over the chrono, a little left, right up or down also makes a difference.