Do different atmospherics matter when truing DSF on 5700 Elite?

[devldogs55]

So I've got a solid zero at 100 yards at 50*F from February when I was at my local range - 400ft altitude and a DA that I recorded but didn't look at before this post. Since working a few kinks out that were all my fault - the Kestrel has now been dead nuts accurate for me out to 830 yards, and I'm pleased with that. My velocities come from a Labradar, and I chrono every shot I take nowadays so I'm always keeping track of my average.

This last weekend, I got to go up to my new spot where I can shoot 1,200 yds in the Cascades at 4,200ft altitude. I'll post a pic of my environmental below. Needless to say, it was much different. So a couple of things I did/want to do. My zero velocity (and typical average at my local range) is 2680 at 50*F and has been that way all winter. Up in the mountains, it was 86*F and my velocity was 2719. I entered my change in velocity/temp into my gun profile, but I'm wondering if the drastic difference in humidity, altitude, DA etc... are accounted for when I enter that information in.

Pretty much the same concern with truing my DSF. Kestrel had me dial 11.9mils at 1200 yards, and it actually needed 12.0 for a hit. Can I just leave atmospherics out of my head, and let the Kestrel do it's magic behind the scenes? That way, if I go into the desert of Central WA and shoot 1200 yards with completely different atmospherics/altitude I will not have messed up its calculations by telling it I needed 12.0?? The 1200 yard shot was also at -9* decline.

If I'm doing this right, I should just record my corrected DSF as +0.1, is that right?

EDIT: I just noticed that the DSF range it recommends for me is 1403. I'm just a tad bit shy of 90% of that - but I can get a good 1300 next time I'm out there so I'll give that a shot. I did notice that sitting here in my living room with a DSF of 1.000 (uncorrected) it is giving me 13.3 mils, so right now if I entered my correction that I noted up on the mountains it would probably be incorrect because I'm not in those conditions any longer... is that right?

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[_Windrider_]

So AB is more accurate the more MV at different temps it has. If you look in the gun profile, you can enter i think up to 5 different MV values. It's best to have over a variety of temps. Of course use what you have and change as you gather more data. I have mine from 35f-90f. This helps it determine avg Chang in MV in fps/degree so when you aren't in an exact condition from which you have collected it can get very very close. Say you have only up 75f at 2800fps, but you are shooting at 80f. It can estimate your 80f MV at say 2820 if it knew your avg change was 4fps/degree. That make sense? DSF is for shooting beyond transonic. It's likely your difference was just a change inMV.

 

[devldogs55]

Yeah I think that makes more sense than what I was thinking.. so does that mean that I shouldn't be truing my DSF, but I should be truing something else?

 

[_Windrider_]

You should be truing the MV. You have your zero MV which is saved in your zero atmospherics. You have the MV table which helps when you don't know your actual MV. But since you do know because of the LR, you should be putting in your actual MV and since the kestrel is getting actual atmospherics your calculations should be dead on.

Now that .1 diff could be Spin Drift. Many believe that AB oversestimates SD. You could turn that on and off and see what happens. For me, I leave it on because frankly I'm just not that good where .1 matters.