Temp based DOPE

[DocRDS]

So was out at the weekly league shooting and my DOPE was off at 1000 (vertical). I thought I had my ballistics solver up to date with the current weather but I was at 9.4 instead of 8.6 mils. (was Hornady Match ammo, so i dunno what powder)

Since it was a nice range and we had velocity at 1000, I back calculated my MV and had lost about 60 fps (80F to 30 F).

DO I just add this as another datapoint to my DOPE records, as I don't see anything on the kestrel about adjusting MV for temp (I had done the imputs to get correct DA and went from 8.2 to 8.6 Mils). I can get some wild weather swings from visiting Doc jr in Texas (110F) to winter up here in sub-canada (realistically down to 0F--usually stuff gets called below 0 and there is no long range hunting due to those tree things) so is this just somehting I measure and take into account?

 

[6.5SH]

There is an MV temp table function.

Let's Talk About MV Temp Tables In Ballistic Calculators!

First who uses this feature and how much of a difference does it make vs not? Second I understand temperatures affecting powder burn rates and therefore affecting MV and that is what the MV Temp Table is for, but doesn't the Kestrel assume the ammo temperature is the same as the ambient/air...

www.snipershide.com

As they discuss there, are pros and cons to either method.

 

[TheOtherAndrew]

Just to make sure Ill ask - did you confirm your zero on same day as this variation occurred?

Also, Im unclear did you use a chronograph for new MV number (and what did you use to get initial MV); or was it via a ShotMarker system; or simply a reverse calculation from real drop vs tryDOPE calculation on ballistic solver?

I ask because in my experience a >1fps/degF change is more than Ive ever encountered in factory Hornady match - I believe I was in the neighborhood of 0.2 - 0.6/degF with match Hornady depending.

Lastly, you may have an overly high compensated MV combined with overly low BC when originally truing data. Do you have a LabRadar or MagnetoSpeed for direct measurement - what is that number (and or what barrel length are you using)?

I guess very lastly lol Ill ask what caliber are we talking about? perhaps if its a .308 in -1000DA you are running into <mach 1.2 and could be more of a DSF issue?

*Couple things to consider - then again I could just be under informed and your ammo does have that much temperature sensitivity...