anyone have a ballistics soft ware calculator with cold weather

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brybenn

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I'm having issues today as I missed 4 shots today. I looked out the Window and saw 2 coyotes sitting in the field behind the house. I managed to get to my rifle and ammo and sneak out the door past the truck and lay up by a snow bank. I can hit my 8" steel plate at 650 yards consistently with no wind and warmer temps. My flags are still out there. There was very little wind. This pair of coyotes were just past my flags. Cartridge is 2506. Bullet is vmax 75 gr. Bc is .29. 3550 fps mv. Range paced off 690 yards. They stood up broadside an started to trot to the left. I touched off wit my 650 yard holdover just on the big ones back. Saw snow fly over his back and they run circle and look back. I fire again same result. Each time they get further out. Anyway 4 shots missed in front of my lady. I go in and she says she thinks I hit the one that trotted off slowly with his tail straight out behind him. I give it an hour and head out. I find the tracks and the first bullet landed right in front of the tracks. The other 3 marks in the snow were between 40-50 yards behind the tracks. Now my question is was I over or under the last 3. Assuming a coyote is 24/26" tall the math eludes me. Bullet impacts in snow were 730 750 and 790 yards. The first hit 690 yards. The tracks for the others were standing 690 710 and 740

I'm going to drag my plate out there tomorrow but it's bothering me not knowing if I was high or low.

I went for the walk and saw one of the Yotes trot out in the neighbour's field and curl up and lay down bout a km out. I tried calling he'd look at me but wouldn't get up. I followed his hour old tracks a few hundred yards with no sign of blood. I clearly missed

Powder is varget if anyone has a ballistic software program that can give me trajectory I'd much appriciate it

I even recovered 2 fired vmax bullets in perfect shape minus the red tip. How it loses the tip but remains intact I don't know. I other 2 hit harder snow and blew up. I found their red tips
 
Ultra cold means denser air. Velocity does change with temperature too. Varget is pretty stable but can and does change.

Better yet you should download or buy a ballistic software and play with it. Lots can be learned from shooting, paying attention, recording results and furthering your experience.

How did you know your original velocity? Cbroo?
 
I use the Sierra program which requires Barometric pressure, relative humidity, elevation and temperature. I normally ad a 5 mph wind at 3 o'clock.
The closer the velocity is to the current conditions, the more accurate the results will be.
Assuming your 3550 was at 70 degrees, and using the same velocity at 0 degrees, The velocity was about 170 fps less at 700 yards when colder.
You would have to re-establish your cold weather velocity. If the 3550 was your cold weather velocity, at 700 yards you are down to 1384 fps.
I shot a coyote at 368 paces paced slightly down hill. It was 386 paces walking back. The length of your pace would be critical as my program uses yards.
 
Thank you for the help. According to jbm software there is 23" difference from 650 to 700. I most have been just over them. My chrony says 3479 3484 and 3478 this morning but. It's 5 degrees F.
 
I used Ballistic AE for iPhone. It has you input all the variables for weather when you zero the rifle then gives you firing solutions that account for changes in temp. It works really well and fast but is pricy. I noticed a 2 MOA difference from summer to winter with 168gr .308s at 300 yards. That would only be compounded at 600+. Because of air density.
 
JR86 said:
I noticed a 2 MOA difference from summer to winter with 168gr .308s at 300 yards. That would only be compounded at 600+. Because of air density.
Click to expand...
2 MOA at 300 yards isn't air density. Scope and rifle/bedding expansion and contraction can make a big difference.
Annual temperature extremes more like 2" at 500 yards. As brybenn noted, 20m rangefinding errors at 500 yards can be a couple of inches.
 
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