.17 Cal. crazy Garmin Velocity spread numbers

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IndexFinger

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Anyone shooting a Small/fast bullets ( .17 Cal. ) , ever get crazy erratic Velocity spreed numbers with your Garmin Chrony . And I mean BIG spread hundreds of FPS between shoots .

I just went yesterday to do the 1st rounds out a .17 Remington . To lay down a base for Vel. on the Loads, and sight-in the scope on paper same time .
I shot 1st ( 5 ) rounds @ 24.5 grain. I had some crazy #'s spread on those 1st 5-rounds over the Garmin when setting a Zero on scope.

Then 'dirty bore' , I shot ( 5 ) more follow-up rounds about 20 minutes latter over the Garmin Chrony.
And Here in Pic. of the Garmin #'s / 25 grain bergers / 25.0 CFE 223
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25.5 Garmin.jpg

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Bench.jpg

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group.jpeg

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I took my AR and shot a few rounds over the Garmin about 15 min. after getting the crazy #'s with the .17 Cal, and the .223 were tight #'s over the Garmin.
Really weird on the .17 Cal. I never seen a Cal. that the Garmin would not pick-up and give a accurate reading for Velocity. I always get accurate for every other Cal. I ever run across it for setting up Loads and setting up ballistic holdovers.

Here Pic. of AR Garmin #'s 15 min. latter over the Garmin , and it has zero problems with the 223 and sierras reading the bullets flight.
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AR.jpg

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I tried a friends Magnetospeed chrono on my 17 Rem one time and it would not read the shots at all. I was not aware there was any settings that could be changed on those chronographs.
My guess is the issue is your Garmin, or may any other chronograph for that matter shooting that small of a bullet, and not your load. Especially given your group size where 4 of the 5 look to be about 1/2 MOA. Not sure what the answer is except to try a couple different chronographs but based on my experience, they have difficulty picking up that small of a bullet traveling at 17 Rem velocities.
 
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JUST a thought... try sitting the garmin higher to be in line in height with the bore. My only thought is because the bullet is so small that the doppler radar might pick it up better.
Don't own a Garmin so can't say, but the Labradar I have like to be close to the same plane as the barrel. Just a thought might not work, then again ???
 
I going to loadup a few different loads this weekend and give it another try using the Garmin.
It has to be the .17 bullet size that is the problem. I keep the Garmin on the factory suggested placement positions with 224, 6mm, .30's and it is always GTG. .

But the Garmin is trying because it is showing inconsistent crazy Vel. #'s . It's like the Garmin just can't quite grab hold of the little .17's as I had a whopping STD DEV. of ( 191.2 ) on those 10 Rounds I ran by the Garmin . and 300 FPS difference between shots is pretty BIG discrepancy .
So I will try getting it close to the line of bore as possible on the next range trip.
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