Elevation Correction Issues

Blacktail

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May 12, 2006
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547
Finally got a chance to shoot 500 and 1000 today. I used the gunwexrks ballistic calculators and at 1000 it was way off. For example my 7/08AI pushing a 120 ttsx at 3150 called for 20 MOA adjustment after a few rounds finally saw vapor trail hit low went to 29 MOA and scored hit. That baffles me. There was a 15 mph head wind. I am not sure if maybe my muzzle velocity was off or maybe just me but 10 Moa off seemed odd to me. New to shooting this far everything has been 500 and in prior but also noted at 500 it was a MOA off meaning called for 5 MOA and used 6. Thanks for the help
 

RockyMtnMT

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Atmospheric inputs, zero, vel, bc, scope click values, and every rifle seems to have a different effect on the bc. Your solution is off a lot. Could be a bit of everything? At 1000y the retained vel is getting very low with this combo and it may just be beyond its ballistic ability.

Steve
 

Barrelnut

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I think you have some information entered incorrectly in the ballistic calculator. I just ran the 3150 FPS with a 120 TTSX with G1 BC 373 and a 15 MPH headwind and got 28.2 MOA for 1000 yards. I used the Shooter app on my Android. That is much closer to the 29 MOA you were successful with.
 

RockyMtnMT

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I think you have some information entered incorrectly in the ballistic calculator. I just ran the 3150 FPS with a 120 TTSX with G1 BC 373 and a 15 MPH headwind and got 28.2 MOA for 1000 yards. I used the Shooter app on my Android. That is much closer to the 29 MOA you were successful with.
I was just about to say that, I'm not sure what the zero is but 20moa sounds really low of the top of my head.

Steve
 

codyadams

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At 1000, 20 MOA is about what my .260 AI uses sending 147 eld-m's at 3040 fps (20.25 moa to be exact), at 6600 ft elevation. No way a 7mm-08 is doing that with the low bc 120 grain barnes, in any practical atmospheric condition.

Check and double check your inputs, something is off . You possibly entered the G1 bc as a G7 bc.
 

HARPERC

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Jan 28, 2011
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Spokane, WA
...Could be a bit of everything? ......

Others have plugged in ballistic solutions closer to what you're seeing so that should have you closer to the mark.

Most of our equipment comes with +/- tolerances, and when they offset each other life is great. When they don't it's tough sledding, and isolating one thing can be difficult.

Unless you measure, and monitor every thing, you're guessing, and the farther you shoot the bigger the error.

I saw David Tubb talking ELR, he was using a chronograph for every shot to ensure he didn't chase a zero based on a round that just was on the low side velocity wise.
 

Andrew Massi

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Jun 4, 2018
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Lincoln Ca
At 1000, 20 MOA is about what my .260 AI uses sending 147 eld-m's at 3040 fps (20.25 moa to be exact), at 6600 ft elevation. No way a 7mm-08 is doing that with the low bc 120 grain barnes, in any practical atmospheric condition.

Check and double check your inputs, something is off . You possibly entered the G1 bc as a G7 bc.

Unless that ttsx is doing 3550 ;-)
 

Blacktail

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May 12, 2006
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547
I just did same thing and came up with 30 moa. The big issue was my 7 mm STW it was way off too so changed things and Ted when I clicked on the drop chart things weren’t changing maybe a comparability issue with my Mac and the gunwerks site not sure but thanks for all the input guys. Which app are most of u running on iPhones?
 

The Oregonian

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Jul 20, 2012
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Missoula, Montana
I just did same thing and came up with 30 moa. The big issue was my 7 mm STW it was way off too so changed things and Ted when I clicked on the drop chart things weren’t changing maybe a comparability issue with my Mac and the gunwerks site not sure but thanks for all the input guys. Which app are most of u running on iPhones?
I run shooter...but in the field I use a G7.
 

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