LabRadar Review - 12/5/15 Update to OP

[Magload]

Why do you need a remote mic for 22LR I have never had one that did not read on the LR? The biggest bunch of my testing has been with 22LR in rifle and pistol I place the side of the LR about 4 inches from m the LR and set on 1 the highest sensitivity.

Have not had anyone shooting beside me trigger my LR and the shooting positions are only about 4 foot apart. If you are running the new Rev. did you get a arrow showing on what side of you the triggering shot came from? If it was from the side opposite your gun you can add a thick piece of foam or something to deflect the sound wave. If it is both side maybe lowering the sensitivity so it just picks up your shots.

 

[ROK]

Why do you need a remote mic for 22LR I have never had one that did not read on the LR? The biggest bunch of my testing has been with 22LR in rifle and pistol I place the side of the LR about 4 inches from m the LR and set on 1 the highest sensitivity.

Have not had anyone shooting beside me trigger my LR and the shooting positions are only about 4 foot apart. If you are running the new Rev. did you get a arrow showing on what side of you the triggering shot came from? If it was from the side opposite your gun you can add a thick piece of foam or something to deflect the sound wave. If it is both side maybe lowering the sensitivity so it just picks up your shots.

Suppressor.
Or should I say suppressor(s). I've shot two different 'cans' (Sparrow and a Ryder) on this rifle and both cans cause problems w/ shots not recognized. I ordered the mic to help the unit out. Are you shooting suppressed?

I don't remember an arrow to select the triggering side. I look for it when I have it out again.

Glad you have had success w/ .22 rimfire. I enjoy the caliber too and look forward to usable results with the new mic.

 

[Magload]

No I can see that a suppressed gun would be a problem. I keep wanting to get a can but it is low on the list of stuff I think I need to have.

The new Rev lvl shows on the top of the screen the mic that recorded the shot.

 

[Nemo288]

The latest (1.1.4) firmware is available at:
http://www.mylabradar.com/admin/incoming/20160705094509_LBRfwa114b100_en.zip
I have not had an opportunity to use the LR with the newest firmware yet. :|

 

[Nemo288]

LabRadar vs. Magnetospeed

I did do some shooting using my 17" .445 Encore with the MS mounted on the barrel AND the LR beside it.
I had some initial trouble triggering the LR which, this time, was mounted on a tripod but got that sorted out quickly.
I needed to get as close as I could to it without knocking over the tripod
Here are the results:
LabRadar...MagnetoSpeed
Horn .430" 300gr. XTP, 30 grains I-4227, *-*, WLP, 2.08"
....................1801
....................1825
1809.............1818
1819.............1826
1818.............1830...predicted MS X= using the data fit formula below:
X=1815.....X=1820..........1825
SD=5.5.....SD=11

COP .429" 200gr. SCHP, 33.5 W296, *-*, WLP, 2.1"
....................2210
2213.............2232
2269.............2285
2224.............2239
2248.............2265
X=2239.....X=2246..........2255
SD=25.......SD=29

Same as above except 34 grains W296
....................2253
2253.............2268
2249.............2266
2224.............2246
2253.............2267
X=2245.....X=2260.........2261
SD=14.......SD=9

Same as above except 34.5 grains W296
2253.............2266
....................2297
2311.............2328
2295.............2305
2239.............2257
X=2274.....X=2290..........2290
SD=33.5....SD=29

Same as above except 35 grains W296
2326.............2341
2297.............2319
2291.............2309
2322.............2334
2332.............2349
X=2313.....X=2330..........2330
SD=18.3....SD=16

Air Temp was 78 F and by this time Barrel Temp was 98 F.

Back to
300gr. Horn 44 XTP, 30 I-4227, WLP, *-*
1817.............1812 (this was the ONLY shot where LR was faster)
1800.............1808
1805.............1816
1813.............1824
X=1809.....X=1815..........1819
SD=7.6......SD=6

Right as I was going to compare this load but with the Rifle primer WLR, the Magnetospeed battery died.
Stupid me, no spare in the bag.
I did run a series by the LR and got:
X=1822..........................1832
SD=11.6
So the rifle primer is measurably hotter.
This latter round is one of my standard .445 loads.
The big Hornady .44 300 XTP is crimped in the rear cannelure for this load and gun.

Entering all the shots where both chronos produced data into my HP50g, I got a best data fit formula of:
Y=.9513*X^1.0074 which is a power curve.
This is an attempt to convert or justify the LR data to the MS data which I have a large database of.
As I get more data I expect that formula to change.
I was surprised it is not a linear equation.
As you can see it does a pretty good job at the higher velocities.

My first reaction is that the SD's track pretty well.
This is something Brian Litz's article TwoBoxer posted in another LabRadar thread points out and gives confidence in the LR.
http://appliedballisticsllc.com/Articles/ChronographChapter.pdf
Obviously the MS figures are always higher than the LR.
The MS measures velocity between 3 and 8 INCHES from the muzzle.
I am not sure how the LR figures out where the muzzle is.

 

[Twoboxer]

Couple of things in your fine report interested me lol, starting with where you ended: I'm not sure how the LR figures out where the muzzle is either. Or whether it matters.

First are those old questions I've asked myself before but have been too lazy to ask the LR folks: At what distance (from the muzzle) does the LR capture velocity? Would the calculation for a given shot vary if the LR were in line with the muzzle vs (eg) 12" further back?

Seems that as long as the muzzle is in front of the LR, radar should be able to pick up the moving bullet very quickly. But with some consistent, measurable, presumably quite small delay.

Second is that the MVs from my MS always were higher than my CED optical chrono showed. IIRC the difference was about the same as you experienced in your test. So your results would make (more) sense to me if the LR was measuring or calculating MV at some distance from the muzzle. Which then brings me back to those pesky questions above lol.

Third is my Math degree must be so old now that it never occurred to me to even try to fit the new data against the old. I just erased the old data from the chalkboard of my mind. Probably a good thing though, as I can't figure out why you assumed the relationship would be linear lol. So much for education

 

[Nemo288]

I can't figure out why you assumed the relationship would be linear lol. So much for education

I have no idea why I thought the relationship would be linear.
Maybe just a certain percentage off?
Mostly a WAG
I know I am not going to be able to use that particular formula for handgun velocities as it seems to diverge the slower things get.
The recent data I have for the 44 special is from a ProChrono, but it is such a PITA to set up and use at the indoor range
I can't see making another comparison like this.

 

[Magload]

Guy this math is way over my head. I would need a plug the numbers in calculator to make it work. I didn't have that many numbers from my Prochrono or the strap on chrono. Have you looked at the data that shows the vel and distance in feet every .002 of a second? It shows the velocity at zero time and on this 38SPL load 0.029021 seconds later the bullet is 19.32 feet down range. I am not sure what the SNR is being a electronics tech to me it would mean Signal to Noise Ratio but that doesn't seam to mean much here.

I do not see with how the LR is aimed and the position it sits how it could read MV. The radar cone would have to be 180 degrees. I don't worry myself as all data you see in books and magazines is ussually taken at 10 feet anyway. HV, LV, and AV is good enough for me.

I retested some ammo today that I tested a couple weeks ago and the readings were with in a few numbers in all categories.

I will call them today as soon as they wake up and get to work out West.

 

[Magload]

Here is our answer I just got of the phone. The muzzle velocity is a very accurate number calculated from all the readings taken down range.

have you ever talked with this guy he is very nice and willing to answer all questions.

 

[Twoboxer]

Magload, my guess is that SNR means "signal to noise ratio", ie, how much stronger is the data signal than the interfering noise signals.

Thanks for making that call Gotta eat, go shoot some, and think about it a bit.

 

[Magload]

That is what SNR has always meant to me. This is Doppler radar and what it is seeing is the frequency shift of the return signal. That is why it is so accurate as the known signal that is transmitted is very accurate and the frequency of the return then is used to figure the shift. As the bullet is going away it is a lower frequency. I am not going into doppler theory as you guys probably know that. What ever it works great.

Have you seen the picture of the roll around platform with the built on tripod for Prochrono? I push it out in front of the indoor shooting line with a 10 foot 3 piece PVC pole. I have been attempted to shoot beside the LR, we can't say "over" anymore then over the Pro and see what the difference is. What keeps me from doing it is if there is a difference that will bother me. Working in a Navy calibration lab for 12 years I always have a doth when I look at a readout. I know that very high priced digital instruments have a calibration cycle and need adjustment.

 

[Nemo288]

strap on chrono.

ROTFLMAO
You don't want to know what went thru my head when I read that!

I was a bench and control room tech-engineer for years and had to haul gear down to Chicago once a year to be calibrated.

I guess even though the trigger times can vary all over the place due to the actual placement of the muzzle,
the timing of the first radar return tells the box exactly how far away the bullet is at that time and then they extrapolate the "muzzle" velocity.
I would guess they set it to 10 feet as that is what most optical chronos say to use.
I sometimes have to go to 15 feet if there is great muzzle blast.
It sure is not giving the numbers close to the muzzle the way the MS does.

 

[Magload]

He said that due to all the readings it takes every yard that the MV calculation is right on.

 

[Twoboxer]

He said that due to all the readings it takes every yard that the MV calculation is right on.

OK, did some shooting and some thinking. Always dangerous

On the one hand, I don't see how any back-calculation can be (perfectly) accurate because LR has no idea where the muzzle is. All it knows is where the LR is . . . relative to the bullet of course.

But let's say the LR is (eg) 6" back from a rifle's muzzle. And let's say the LR uses the stream of downrange data to calculate what the velocity had to be at the point of origin (actually the LR) to produce that data. (AFAIK all done without atmospheric data.)

The LR would assume the bullet had traveled 6" further to reach the point(s) of measurement than it actually did. That would be a small error, maybe around 0.7% if the average distance of the measurement stream were say 30 yds.

If I got this right, wouldn't that lead the LR to over-estimate what the muzzle velocity had to be to produce the down range measurements?

But, using Nemo's MS data as the standard, he's seeing exactly the opposite.

But the MS has some potential issues too. The distance between the sensors (or the sensors' measurements) only has to be off spec by 1mm to produce the same kind of error.

I think I give up lol. This ex-computer geek turned desk jockey will leave it to the equipment techs lol. And I'm glad I never tried to reconcile the chrono data to either my MS or my CED.

 

[Magload]

I agree but look at these numbers for my 38SLP.
At 19.32 feet the vel is 664.42
At 20.65 feet the Vel is 663.61
---------
0.81
20.65 feet
19.32 feet
-----
1.33 feet
The data does show 671.18 at 0.0 feet so that is a loss of 6.76 in the first 19.32 feet or a loss of 2.85 fps in the first 19 feet. Like I said at the muzzle to 6" it is probably less so I ma not going to worry about it.

So in 1.33 feet the bullet looses 0.81 FPS it probables looses less then that the first 19 feet so we are talking less then a fps 6" from the muzzle. Not something I am going to worry about.

I am not a math wizz by far but I still think this LR rocks.

 

[Twoboxer]

. . . but I still think this LR rocks.

I'm good with that