Help me understand Truing Muzzle Velocity

[crossgun]

So I have reviewed the Kestrel MV Truing information and watched the video by X-ring but have a question about changing the MV after truing. Is truing done on every outing or set and forget? What happens after I true then a month later my MV is 10 fps greater or slower? How do I account for that?

Get speed from my Garmin and enter the data. Zero at 50 yds and true MV to match my impacts at 200 yds. Lets assume I did that with a chrono average reading of 1080 at 50 degrees. Its now 75 degrees and the chrono average reading is 1097. Now do I have to re-true the MV? How would I input the MV change without affecting the already established curve?

Seems to me that getting a chrono reading on every outing is the only thing that I can control. Am I better off to Cal DSF at numerous distances out from my zero to get a "truer" curve and then adjust MV based on the actual reading of the chrono each outing?

 

[Long Range 338]

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Watch the videos here, they walk you thru the process of using the Kestrel and truing.

 

[Taylorbok]

as far as temp goes either record your temp on several days at different temps or go to the range on a 72* ish degree day, put some ammo in a cooler with ice and some on the heater on high in your truck, use a temp gun to get the ammo temp, shoot it and record that. Enter into kestrel tables.

I'm assuming this a 22LR based on the speed. If you want to true DSF to get a true curve that would be a good way to go about it IMO. From what I've experienced I've been able to run off what the kestrel spits out pretty darn good to 450 ish yards.

 

[J_D]

So I have reviewed the Kestrel MV Truing information and watched the video by X-ring but have a question about changing the MV after truing. Is truing done on every outing or set and forget? What happens after I true then a month later my MV is 10 fps greater or slower? How do I account for that?

Get speed from my Garmin and enter the data. Zero at 50 yds and true MV to match my impacts at 200 yds. Lets assume I did that with a chrono average reading of 1080 at 50 degrees. Its now 75 degrees and the chrono average reading is 1097. Now do I have to re-true the MV? How would I input the MV change without affecting the already established curve?

Seems to me that getting a chrono reading on every outing is the only thing that I can control. Am I better off to Cal DSF at numerous distances out from my zero to get a "truer" curve and then adjust MV based on the actual reading of the chrono each outing?

It's set and forget. Watch the X-Ring video......you get some chrono speeds of at a minimum of at least 30rds but a box or 2 of the same lot would be better......zero at 50yds.....true MV at 200 on that day and mark the temp where Ray inputs at the bottom, then you can DSF from 250, 300, 350, 400, etc....always from near to far from 250 out. Then you're set. The kestrel will capture environment data and adjust for temps for you from then on for elevation.


......if you happen to chrono at different temps with the same lot, input the higher or lower temp MV for data capture. Here in TX we get wild temp swings, but check the temps every stage.

 

[LR1845]

It's set and forget. Watch the X-Ring video......you get some chrono speeds of at a minimum of at least 30rds but a box or 2 of the same lot would be better......zero at 50yds.....true MV at 200 on that day and mark the temp where Ray inputs at the bottom, then you can DSF from 250, 300, 350, 400, etc....always from near to far from 250 out. Then you're set. The kestrel will capture environment data and adjust for temps for you from then on for elevation.


......if you happen to chrono at different temps with the same lot, input the higher or lower temp MV for data capture. Here in TX we get wild temp swings, but check the temps every stage.

THIS RIGHT HERE^^^ I used Xrings way of truing and my kestrel has been money the last 3 times out out to 300yds, the more temp readings you can get the better.

 

[021411]

I usually use a CDM if it’s available and get a solid zero in while at the same time getting MV from the chrono. I usually do a long string of 20-25 rounds.
I do CAL MV at 200y on a 2” tall water line. I’ll make the adjustment if needed and then move to 300y with a 3” water line. If needed I’ll CAL DSF. Once that’s dialed in I’ll verify my data by shooting 100-300 to confirm.

As someone mentioned Texas gets crazy temp swings. The last time I’m collected data it was around 73-75 degrees. Match temps have gotten into mid-80s and I’ve hit out to 328y with no issues. Once it starts to getting to be 80’s in the morning hours I might gather new data (MV) check/re-true. 80’s in the morning usually equates to 90’s mid match.