LabRadar question

[tbrice23]

Thinking about getting a LabRadar but, was wondering how difficult they are to operate. Saw a fellow at the range yesterday and he kept pushing all kinds of buttons. Didn't talk to him so I don't know what he was attempting to do. Can this machine be put in the "rifle" mode and then used? I don't need all types of info for my shooting. Just would like velocity and averages.

So, my old chrono was the Caldwell Ballistics Precision Chrono ( the upside down one). I really have no complaints about this chrono. The Labradar is a PITA compared to the old one. It wants to be in the 6" distance setting only. I shoot three or more rifles in rotation at the range and have to continually adjust the muzzle in relation to the Radar because some rifles have no muzzle brake, others have 45° brakes, some have 90° brakes. The unit disconnects six or seven times each session and have to manually reconnect pairing to the Labradar! You have to constantly look to make sure the muzzle blast didnt move the alignment which it often does.

My Ballistics Precision chrono never disconnected from my app, I never had to reposition the muzzle or manually arm before each shot or stop and make sure the **** thing isnt blinking or turned blue before taking a shot, all the checking and arming and reconnecting is VERY distracting and doesn't help my concentration on shooting at all! All I had to do with my BP chrono was shoot.

Maybe I'll get used to being distracted while trying to concentrate.

 

[entoptics]

Does anyone know how to calculate true BC from the velocity readings?

I use JBM ballistics.

Rather than using the canned output for the various distances, I will open each individual tracking file in Excel, plot the data (distance vs velocity). If the data makes a nice linear trend, I'll pick a couple of points as far apart as possible in distance, and plug those into the calculator.

You can definitely use the calculated distance points from the LabRadar output, I just find more variability using that method. It helps to fire multiple shots and calculate the BC multiple times. This will give you an idea of how much variation the calculation brings into things.

Be sure to CAREFULLY record environmentals for each shot. I suggest using a real barometer/thermometer/hygrometer to measure pressure/temp/humidity. Getting it from something like a weather app, which may be fetching data from a weather station miles from your location, may not be accurate enough for good B.C. calculations. Relatively cheap weather station thermometers often have T and RH, and most modern smart phones have built in barometers, so you can get an app to give you the real station pressure right on your phone.

 

[entoptics]

...The unit disconnects six or seven times each session and have to manually reconnect pairing to the Labradar! You have to constantly look to make sure the muzzle blast didnt move the alignment which it often does...

The app can certainly be frustrating, but something to note is that it doesn't need to be connected to collect data. Only for arming and changing strings/settings. I set the armed time to the maximum 300 seconds, which minimizes the "blue light" problem. I arm it, shoot my string, and don't touch the phone again until I need to make a new string.

Another quirk that causes connection problems is if the phone goes to sleep while the unit is armed (orange light), then the unit goes unarmed (blue light), then you wake the phone back up. This causes it to stop responding. You can mitigate this by keeping the phone and chrony in the same state. In other words, when you finish a string, immediately disarm the chrony with the phone. That way if the phone goes to sleep, when it wakes up, the chrony is still in the same state as when the phone was awake last.

Regarding the blast shaking things out of alignment, I suggest pushing the muzzle even further past the unit. I've had no problems with triggering or tracking, with the muzzle as far as six inches in front of the unit.

Sorry it's so frustrating for you. I'm so used to the quirks now, that I don't really think about them much anymore. It sure would be nice if the manufacturers address them, but I'm not gonna hold my breath. Perhaps another radar based solution will come along soon, and perhaps the competition will startle LabRadar enough for them to actually address these problems. For now though, they are the only game in town.

 

[tbrice23]

I use JBM ballistics.

Rather than using the canned output for the various distances, I will open each individual tracking file in Excel, plot the data (distance vs velocity). If the data makes a nice linear trend, I'll pick a couple of points as far apart as possible in distance, and plug those into the calculator.

You can definitely use the calculated distance points from the LabRadar output, I just find more variability using that method. It helps to fire multiple shots and calculate the BC multiple times. This will give you an idea of how much variation the calculation brings into things.

Be sure to CAREFULLY record environmentals for each shot. I suggest using a real barometer/thermometer/hygrometer to measure pressure/temp/humidity. Getting it from something like a weather app, which may be fetching data from a weather station miles from your location, may not be accurate enough for good B.C. calculations. Relatively cheap weather station thermometers often have T and RH, and most modern smart phones have built in barometers, so you can get an app to give you the real station pressure right on your phone.

I

I use JBM ballistics.

Rather than using the canned output for the various distances, I will open each individual tracking file in Excel, plot the data (distance vs velocity). If the data makes a nice linear trend, I'll pick a couple of points as far apart as possible in distance, and plug those into the calculator.

You can definitely use the calculated distance points from the LabRadar output, I just find more variability using that method. It helps to fire multiple shots and calculate the BC multiple times. This will give you an idea of how much variation the calculation brings into things.

Be sure to CAREFULLY record environmentals for each shot. I suggest using a real barometer/thermometer/hygrometer to measure pressure/temp/humidity. Getting it from something like a weather app, which may be fetching data from a weather station miles from your location, may not be accurate enough for good B.C. calculations. Relatively cheap weather station thermometers often have T and RH, and most modern smart phones have built in barometers, so you can get an app to give you the real station pressure right on your phone.

I use JBM a lot.
So once I get the corrected BC, enter the BC, weight, length, caliber, environment to get my Trajectory/ Drift chart.
Correct ?

 

[entoptics]

I use JBM a lot.
So once I get the corrected BC, enter the BC, weight, length, caliber, environment to get my Trajectory/ Drift chart.
Correct ?

That's how I'd do it. I use the specific JBM B.C. Calculator (Velocity) to get the real B.C., then input into the regular ballistics calculator for drop data.

I've checked the BC on a several bullets, and only the Nosler Accubond deviated significantly from the advertised value. I think the usefulness is for bullets that don't have an advertised B.C., or for calibers that drive the bullets significantly faster or slower than "average". If you're shooting 208s in a 308 for instance, the advertised B.C. was probably listed for a much faster round, and therefore it's worth figuring it out for your particular load.

 

[tbrice23]

That's how I'd do it. I use the specific JBM B.C. Calculator (Velocity) to get the real B.C., then input into the regular ballistics calculator for drop data.

I've checked the BC on a several bullets, and only the Nosler Accubond deviated significantly from the advertised value. I think the usefulness is for bullets that don't have an advertised B.C., or for calibers that drive the bullets significantly faster or slower than "average". If you're shooting 208s in a 308 for instance, the advertised B.C. was probably listed for a much faster round, and therefore it's worth figuring it out for your particular load.

Funny you said that because I just plugged in the 200gr AB... came up with a lot lower number than advertised. But the environment today was like the Amazon rain forest.

 

[entoptics]

Funny you said that because I just plugged in the 200gr AB... came up with a lot lower number than advertised. But the environment today was like the Amazon rain forest.

What did you get? I got about 0.56 if I remember correctly. That isn't huge difference from the advertised 0.588, but it starts to make a difference at the outer edge of hunting ranges. Some rough calculations suggest it's a couple inches more drop at 700 yds.

 

[tbrice23]

What did you get? I got about 0.56 if I remember correctly. That isn't huge difference from the advertised 0.588, but it starts to make a difference at the outer edge of hunting ranges. Some rough calculations suggest it's a couple inches more drop at 700 yds.

Im at 700 asl. .566 g1 the first time...dont known what I did wrong.

Calculated a different shot ( linear slope) got... 596 g1, V0 is 3206

 

[tbrice23]

Interesting! Different shot. .606 g1!

 

[tbrice23]

And

So I guess I'll enter several BC results and average.

 

[entoptics]

AndView attachment 135471
So I guess I'll enter several BC results and average.

One thing I see that may be inflating the BC you're getting is that you have standard sea level pressure (29.92), but "pressure is corrected" as no. Barometric pressure is a key input for getting an accurate BC.

The fact that you're getting the same answer over and over is a good sign, but I suspect you're actual atmospheric density is lower than what your inputs are telling the calculator, therefore it thinks the air is "thicker", and is returning an inflated BC.

As I mentioned above, if you want to get as accurate a BC as possible, you need to record the actual pressure/temp/humidity where and when you took the shot. If you can't, you at least need to enter a corrected station pressure from a nearby weather provider.

 

[tbrice23]

I entered it from today from Weatherbug

 

[tbrice23]

That station is about two miles from the range.

I'll see if my results are the same on my next session.

 

[entoptics]

That station is about two miles from the range.

I'll see if my results are the same on my next session.

If the elevation is the same (out here, something 2 miles away can be 3000 ft different), then you're probably OK using a weather station like that. You'll need to select "Pressure is corrected" in JBM though, as weather stations report a sea level normalized pressure.