Making sense of Zero and dialing

[UndFrm]

I am perplexed with this. Still fairly new so perhaps I'm missing something obvious?

6mm Dasher, 30in barrel. I zeroed at 100y Used a free ballistic calculator to get the dial at 500y, showed 9.1 but what was accurate on paper was 8.5
No problem, environment etc affects.

Zeroing temperature was 68F and this was at 13F, if that affects.

300y - calculator showed 3.7, actual was... 0.5 up

What doesn't make sense is how my actual dial is up by only 0.5 at 300y when I zeroed at 100y
I haven't had a chance since then to verify at 100y again, that's my next step. Is there something am I missing or for some reason my zero changed drastically on its own?


Thank you

 

[OREGUN]

Are you confident in the zero?
Is your scope and your calculator marked/reporting in MRADS and not MOA or vice versa? Are you mixing units is what I’m asking.
What are you using for bullet speed in the calculator?

Your 300 yard dial should be closer to 1 mil but your 500 yard should only be around 3 mils. Or 4.5 and 10 moa.

 

[UndFrm]

Are you confident in the zero?
Is your scope and your calculator marked/reporting in MRADS and not MOA or vice versa? Are you mixing units is what I’m asking.
What are you using for bullet speed in the calculator?

Your 300 yard dial should be closer to 1 mil but your 500 yard should only be around 3 mils. Or 4.5 and 10 moa.

Fairly confident in zero.
Verified that the scope and the calculator are both MOA.
For the speed, I have been using an average of 2890fps which I gathered using a chronograph. I do understand that since it's an average and the temp will affect the speed as well, this won't be 100% accurate.

 

[Aftermath]

How many rounds through the pipe?

 

[UndFrm]

How many rounds through the pipe?

Almost 600
I did zero it when the round count was 250, but updated the speed in the last approx 200 rounds. Did speed up.

 

[Aftermath]

Almost 600
I did zero it when the round count was 250, but updated the speed in the last approx 200 rounds. Did speed up.

Then it does seem like there is some parameter off in your calculator. I'd go through the Gravity Ballistics process and find good real DOPE. Once you have good actual information, you can alter your inputs on the calculator to figure it out.

 

[OREGUN]

Double check your zero, speed, and verified come-up at 300. Your 9.1/3.7 combo makes sense for a bullet that’s zipping right along…even tweaked to be on at 8.5. The .5 makes no sense at all at 300 yards. You should be up a little over 3 MOA at that distance. Any chance you were mis-dialing or mis-reading your turret?

 

[roostercogburn98]

Scope over bore set correctly in the ballistic app? That will make some difference

 

[mark5pt56]

I am perplexed with this. Still fairly new so perhaps I'm missing something obvious?

6mm Dasher, 30in barrel. I zeroed at 100y Used a free ballistic calculator to get the dial at 500y, showed 9.1 but what was accurate on paper was 8.5
No problem, environment etc affects.

Zeroing temperature was 68F and this was at 13F, if that affects.

300y - calculator showed 3.7, actual was... 0.5 up

What doesn't make sense is how my actual dial is up by only 0.5 at 300y when I zeroed at 100y
I haven't had a chance since then to verify at 100y again, that's my next step. Is there something am I missing or for some reason my zero changed drastically on its own?


Thank you

Maybe look at this??

 

[OREGUN]

With all due respect, get out your kestrel and learn yourself something. Temp changes, elevation changes, humidity, atmospheric pressure…none of that makes a 3 MOA difference at 300 yards. Or even a .3 MOA difference. It’s not the temp or any other atmospheric condition.

Or, for that matter, the scope height over bore with any reasonable value.