Density Altitude In Shooter App?

[Formidilosus]

Thanks Form. Starting over with a new profile was my plan to eliminate errors.

OP: I acknowledge that all my data could be mirage as well...its in the 90's here and 92% RH and raining daily at this time. I'm shooting prone over a vast patch of mowed grass, so the scope is probably 10" above the wet grass.

Oof. That is absolutely having an effect.

 

[TX_Diver]

Waiting for a guy checking pumps to finish. Target at 685 with a waterline on it. 75 degrees at 4k feet elevation. Going to shoot 10 rds and will report back.

I did go to 1.8 on sight height as I think I was measuring from a bit below center of bore.

Just need to not get lost in my turret at 5.3 mil on the swfa lol

 

[TX_Diver]

5.3 at 685. Going to shoot another five and get a measurement.

 

[TX_Diver]

 

[Formidilosus]

View attachment 755100

Thoughts?

 

[TX_Diver]

Thoughts?

1 - I need to learn to read wind better (I knew that though and am not shooting game this far)

2 - up .2 mils. That corrects MV to 2483 or so. But seems to work?

 

[JF_Idaho]

Have you checked your scope elevation clicks with a tall target test? Just to rule that out?

 

[Formidilosus]

1 - I need to learn to read wind better (I knew that though and am not shooting game this far)

Everyone does.

2 - up .2 mils. That corrects MV to 2483 or so. But seems to work?

Why would you go up .2 mils?

 

[Lawnboi]

Be careful trueing anything in less than ideal conditions.

Mirage can have a big effect.

These instances I’ll true for the day, or similar conditions in the future, but wouldn’t lock it in and drive to a different area, and expect it to work.

 

[TX_Diver]

Everyone does.





Why would you go up .2 mils?

Initial solution based on 4000’ elevation and 75F.



So my initial thought was to come up 3.5”.

I took 3.5 / (3.6x6.85) = 1.42 and rounded up to 2.

MV adjustment for 5.5 at 685 is 2473fps.



Playing with it at home and looking at it again I think I should just go up .1 and correct it to 5.4 at 685. Adjusted MV of 2493. This would match my data last time of 4.5 at 610. And (small sample size though) did miss high off my 10” plate with the original correction of .2mil.




let me know what you think though. Happy to answer other questions too on my thought process and learn how to improve it

 

[TX_Diver]

Also, if it helps here was my initial group yesterday after moving scope forward. I went up .1 and right .1 from this. 13 rounds. All off a molinator on a pack

 

[mxgsfmdpx]

1 - I need to learn to read wind better (I knew that though and am not shooting game this far)

2 - up .2 mils. That corrects MV to 2483 or so. But seems to work?

Learning to call wind takes a long time and a whooooole lot of shooting in different wind conditions to even be “decent” at it.

For this trueing application, ignore the wind unless it’s enough to blow you off target, hence the water line. Focus on good/solid elevation holds and let em go.

You have 4 shots within roughly 2” of the water line. You then have 4 shots low and 2 shots high. The larger spaced shot discrepancies are likely your shooting and not “dope”. In general you are trending “low” in this particular built position but again, likely not to do with dope I would guess. What happens if you break position and shoot another 10? Do you trend high instead or continue to trend low?

Looking at it closer, it appears that 7 out of 10 shots are killing shots on deer and elk ignoring wind. Thats much better than most shooters at 685 yards.

If after another 10 from a completely different built position (let’s say on a bench with bags instead of prone as an example) you are still trending low; I’d say let’s bring it up .1 MIL see how many hits you get on 10” gong out of 10 shots.

I think you are already really close or right there. Adjusting up .2 MIL would be too much. You will then trend high no question.

 

[TX_Diver]

Learning to call wind takes a long time and a whooooole lot of shooting in different wind conditions to even be “decent” at it.

For this trueing application, ignore the wind unless it’s enough to blow you off target, hence the water line. Focus on good/solid elevation holds and let em go.

You have 4 shots within roughly 2” of the water line. You then have 4 shots low and 2 shots high. The larger spaced shot discrepancies are likely your shooting and not “dope”. In general you are trending “low” in this particular built position but again, likely not to do with dope I would guess. What happens if you break position and shoot another 10? Do you trend high instead or continue to trend low?

Looking at it closer, it appears that 7 out of 10 shots are killing shots on deer and elk ignoring wind. Thats much better than most shooters at 685 yards.

If after another 10 from a completely different built position (let’s say on a bench with bags instead of prone as an example) you are still trending low; I’d say let’s bring it up .1 MIL see how many hits you get on 10” gong out of 10 shots.

I think you are already really close or right there. Adjusting up .2 MIL would be too much. You will then trend high no question.

The 5 on the left were from the first time I built the position. After seeing the target I adjusted my wind hold and shot the 5 on the right with a new wind hold.

While the wind was consistent I was getting good hits at 605, but as soon as it started getting a bit more variable my hit rate declined rapidly. Especially with the 223!!

good thinking on building the position 10x. Idk if I’ll get a chance to do that before my trip but will keep working at it

 

[TX_Diver]

Be careful trueing anything in less than ideal conditions.

Mirage can have a big effect.

These instances I’ll true for the day, or similar conditions in the future, but wouldn’t lock it in and drive to a different area, and expect it to work.

Makes sense. I was putting my t post in before the sun was up so I wasn’t fighting the mirage this time. But by end of morning it was already 90 when I left at 10 and mirage was starting to pick up.

how far off have you seen it be? .1? Or .5? More?

 

[Lawnboi]

Makes sense. I was putting my t post in before the sun was up so I wasn’t fighting the mirage this time. But by end of morning it was already 90 when I left at 10 and mirage was starting to pick up.

how far off have you seen it be? .1? Or .5? More?

1-3 tenths is not uncommon.

Barring other external factors mirage off your barrel/suppressor can start to make things strange as well, especially in 100 degree temps where your rifle is never cooling.

Any time I need to true at distances such as your looking at(distances well away from transonic) I take a good look at everything else and normally true to the day, document it and look for a cause.

With a known good bullet, correctly working rifle/scope/shooter if I’m changing anything sub 700 yards it’s for the day alone.


How are you gathering velocity? Between the beginning of a big shooting day and the end I almost never see my barrel slow down, and usually see a slight speed up as the day goes on. Much less of a deal with a 223.

Just to give you an idea of what this can do. When I started long range shooting I trued like the internet told me to do at 1000 yards on a soupy summer day. Next week I shot a match with my trued data and was chasing my ass all day. I had trued to conditions that were now not present and I paid for it.

Since then I have moved to good confirmed scopes, good zeros, good solvers and now I can nearly obtain velocity all day wit the xero. I have not run into an instance in a long time, under normal conditions where I have been scratching my head on sub 700 yard shots.

 

[TX_Diver]

1-3 tenths is not uncommon.

Barring other external factors mirage off your barrel/suppressor can start to make things strange as well, especially in 100 degree temps where your rifle is never cooling.

Any time I need to true at distances such as your looking at(distances well away from transonic) I take a good look at everything else and normally true to the day, document it and look for a cause.

With a known good bullet, correctly working rifle/scope/shooter if I’m changing anything sub 700 yards it’s for the day alone.


How are you gathering velocity? Between the beginning of a big shooting day and the end I almost never see my barrel slow down, and usually see a slight speed up as the day goes on. Much less of a deal with a 223.

Just to give you an idea of what this can do. When I started long range shooting I trued like the internet told me to do at 1000 yards on a soupy summer day. Next week I shot a match with my trued data and was chasing my ass all day. I had trued to conditions that were now not present and I paid for it.

Since then I have moved to good confirmed scopes, good zeros, good solvers and now I can nearly obtain velocity all day wit the xero. I have not run into an instance in a long time, under normal conditions where I have been scratching my head on sub 700 yard shots.

Velocity was average of 10 shots across a magnetospeed.

If only hunting out to ~400 would you have any major concerns with the data I’ve got now?

I don’t have many other options aside from just ensuring my max range is within what my data is valid for?

 

[Lawnboi]

Velocity was average of 10 shots across a magnetospeed.

If only hunting out to ~400 would you have any major concerns with the data I’ve got now?

I don’t have many other options aside from just ensuring my max range is within what my data is valid for?

If things are not lining up at 400 yards I’d do more digging. Zero reason things shouldn’t line up at 400 yards. If they are I’d trust the gun and change environmentals only.

I can’t speak to shooter but I use AB and Hornady 4dof.

 

[TX_Diver]

Stuff lines up. I just meant would you be comfortable taking data gathered in these conditions and applying it 400 and under elsewhere?

 

[Formidilosus]

Initial solution based on 4000’ elevation and 75F.

View attachment 755138

So my initial thought was to come up 3.5”.

I took 3.5 / (3.6x6.85) = 1.42 and rounded up to 2.

MV adjustment for 5.5 at 685 is 2473fps.

View attachment 755139

Playing with it at home and looking at it again I think I should just go up .1 and correct it to 5.4 at 685. Adjusted MV of 2493. This would match my data last time of 4.5 at 610. And (small sample size though) did miss high off my 10” plate with the original correction of .2mil.


View attachment 755140

let me know what you think though. Happy to answer other questions too on my thought process and learn how to improve it

The red circle is your group. The yellow line is the center. It’s a “max” of up .1 mil, and with the size it may not be off at all. Anything more than up.1 mil, is not correct.






And yes, true to that, or up .1 mil at 685 yards, and you are good for anything from the muzzle to 685 yards.

 

[TX_Diver]

The red circle is your group. The yellow line is the center. It’s a “max” of up .1 mil, and with the size it may not be off at all. Anything more than up.1 mil, is not correct.

View attachment 755357




And yes, true to that, or up .1 mil at 685 yards, and you are good for anything from the muzzle to 685 yards.

Interesting. So you take the geometric center regardless of how many shots are above or below it? I had “weighted” my estimated center based on where most of them fell.

sounds like I was approaching it wrong though.

I shot the .223 at the same waterline but hadn’t really evaluated it yet as I was rushed and had to leave. While the vertical dispersion sucks it’s still probably going to bring me close enough for any range I’d actually shoot I guess…

TMK at 2622 (10 shot avg). Dialed 5.8. Make an adjustment based on the yellow or maybe slightly below it based on my poor geometry and roll on?




Appreciate the help (both with the shooting and the iPhone art! I am learning on both )