Shotmarker, SD, & Wind

[Bob3700]

Has anyone noticed that when using ShotMarker, the SD of your loads increases when the wind is heavier? Our target is set at 600 yds and each time the wind is in the 10 MPH + area, the SD reading of the loads almost doubles.
Our guess is that the targets themselves are moving in the wind and this effects the SM Chrono data.
Loads that typically register 8-10 SD now show 18-25.
Your experience is?
Bob

 

[RegionRat]

Yes, those are typical observations on ShotMarker. Some of that is the target frame stability, and some of it is just the air density variation with the pressure of the winds.

 

[D-4297]

^^^^^ What he said ! I shot in a E-Target Match yesterday where the winds went from 5 mph , to a blustery and gusting 25 mph .
My loads measured by both a Lab , and a Garmin usually run between 4.2 & 6.0 were reading at fourteen to seventeen . My thought was , Yeah , okay .

 

[gunsandgunsmithing]

May have zilch to do with it but a 10mph wind is 14.6 fps.

 

[Chris Edmondson]

Some time ago when I was looking to retire my Labradar, I inquired about Shotmarker as a chronograph replacement since that's included "free" with it's main purpose, shot marking. The response consensus at that time was that Shotmarrker is not a substitute for a purpose-built chronograph.

I'd reach out to Adam McDonald, he's always been responsive when I've asked about AutoTrickler matters.

 

[DirtySteve]

Shot Marker is not accurate for measuring velocity............. Adam will tell you that.. It is an approximate.

 

[64Rambler]

Yes, have noticed increase in indicated ES/SD at target compared to Garmin at firing line. From a recent 3 x 600 (club level, not NRA);
Wind Garmin SM
3-4 25/7.1 38/11.0
1-2 24/6.3 33/8.9
6-10 30/7.8 69/18.9 (switching wind)

The Garmin data for the 3rd relay is due to the load increasing in velocity with the temp swing of the day, not the wind, I saw a 35 fps increase over Relay 1, and just out of my velocity node.

But like Steve said, SM is an approximation.