Ballistic question - I am stumped

[dfanonymous]

Unless I am missing something drastic, your example shows that the zero range isn't the issue. My rifle is right at 2 moa high at 100. If I zero at 100, (drop my zero 2 moa), I would now need 11.25 moa to hit 600 so still roughly 2 moa more predicted and we are back to making extreme cuts to velocity or bc inputs to force it line up.

No I stand by my first post. This was an example of zero effecting the "numbers" to someone else.

However, you're not going to got me with the ballistic talk. Whatever you're doing isn't working. Just zero at 100y like a normal human being and you won't be on here explaining how it doesn't make sense.

If you want to use a 200y zero, zero at 100y and dial 200y. The keep that setting in the field if you need to use PBR.


The problem is I my self have to assume that you are zero'd at 255y. The fact is, you might say you are and believe you are, but that might not being the case. If you have 2 moa above center at 100y, why not just use an offset setting?

With these questions, it always the basics that trigger garbage in garbage out. If it's "just a tracking issue" or "just humidity" then why hasn't scooby and the gang been able to replicate it?

Even with the ballistic data shown, you still don't get it. The picture with the data using the 100y zero closely matched your real world results.

BC has little to no effect at 600y.
Velocity does…if you're saying it's magnetospeed and labradar'd then you shouldn't have to true anything that much.

Tracking isn't a huge issue at 600y unless you're you're like over a 3% error.

Being a ****** marksmen is always an issue, in which case I bring you back to zero.

#1 We don't know what he's really verifying with his Kestrel, nor how the information is being loaded into software
#2 Everybody confuses air density parameters
#3 You demonstrate your own confusion, while thinking that pressure has anything to do with temperature
#4 You contribute further to #2 with DA (a calculated prediction rather than actual measure)

OP, if you can answer questions in post #6, there is a chance the solution will arise as a simple matter.

You're post is useful and I learned so much about the errors of my ways…thank you.

However, I'm not there with the OP plus I have to be critical of the information because something is obviously wrong. Hence why we are all gathered today.

The chart was a way to show visual representation of how the atmospherics could have been incorrect. All of it is an estimate. Unless there's a datalog or a picture of the kestrel at the time of shooting…..this is a mute conversation…

 

[M Jager]

Have you tried truing your velocity to 600 yards and then truing bc to 1000 yards? What does that look like?

No I stand by my first post. This was an example of zero effecting the "numbers" to you.

However, you're not going to got me with the ballistic talk. Whatever ever you're going isn't working. Just zero at 100y like a normal human being and you won't be on here explaining how it doesn't make sense.

If you want to use a 200y zero, zero at 100y and dial 200y. The keep that set.


The problem is I my self have to assume that you are zero'd at 255y. The fact is, you might say you are and believe you are, but that might not being the case. If you have 2 moa above center at 100y, why not just use an offset setting?

With these questions, it always the basics that trigger garbage in garbage out. If it's "just a tracking issue" or "just a humility" the why hasn't scooby and the gang been able to replicate it?

Even with the ballistic data shown, you still don't get it. The picture with the data using the 100y zero closely matched your real world results.

BC has little to no effect at 600y.
Velocity does…if you're saying it's magnetospeed and labradar'd then you shouldn't have to true anything that much.

tracking isn't a huge issue at 600y unless you're you're like over a 3% error.

Being a ****** marksmen is always an issue, in which case I bring you back to zero.


You're post is useful and I learned so much about the errors of my ways…thank you.

However, I'm not there with the OP plus I have to be critical of the information because something is obviously wrong. Hence why we are all gathered today.

The chart was a way to show visual representation of how the atmospherics could have been incorrect. All of it is an estimate. Unless there's a datalog or a picture of the kestrel at the time of shooting…..this is a mute conversation…

I am deffinately not trying "got you" with ballistic talk. However your example that shows roughly 9 moa at drop with 100 zero only works if we leave the rifle zeroed 2 moa high at 100 yards. And is now way off what I saw in the field at 255 and 400. Having your rifle sighted 2 moa at 100 and telling your ballistics app that it's zeroed at 100 in order make it hit at one specific range seams a lot lot of garbage in.

If I am missing something DF is try explain how zeroing at 100 will fix my issue, someone please jump in and try explain it because to me the math seams very simple.

 

[dfanonymous]

I am deffinately not trying "got you" with ballistic talk. However your example that shows roughly 9 moa at drop with 100 zero only works if we leave the rifle zeroed 2 moa high at 100 yards. And is now way off what I saw in the field at 255 and 400. Having your rifle sighted 2 moa at 100 and telling your ballistics app that it's zeroed at 100 in order make it hit at one specific range seams a lot lot of garbage in.

If I am missing something DF is try explain how zeroing at 100 will fix my issue, someone please jump in and try explain it because to me the math seams very simple.

Sorry, busy morning, for me and rushing my responses. Take no offense to how I talk ****. I'm a equal opportunity ***-hole…year round.

The issue with zero and to my point, isn't about being correct, the issue is organization and being able to verify things as is long range shooting.

So, by zeroing at a 100y, and having a general group center of poa, poi we can eliminate some potential issues:

1) that your offset is entered incorrectly or entered at all for that matter
2) atmosphere was added into your zero
3) That zero is in fact…zero and not a estimate.
4) Accidents are less likely to be inputted into software by over complicating things.


To quickly explain all this, if any of the above is incorrect, your ballistic solution at distance is void. No one here can remotely trouble shoot that, and we aren't there and able to verify and correct for you.

To answer your question, you eliminate or at least mitigate, all of the the above when using a 100y zero. An easy way to tell if is a zero/software contradiction is to zero at 100y and try this whole process again.

Also, just curious …how exactly did you acquire your range of the targets? I'm assuming a laser range finder correct?

Lastly…again…I stand by my first post. In regards to that, I stand by what I said about atmospherics. You'll have to walk the group through your entire procedure and how you acquired those number before we, or at least I, can toss that aside and dismiss it.

Often enough, 25-26.5 inHg is what is experienced during a typhoon. If any pilots are on here, by all means…tell me when or when you wouldn't be concerned about said pressure…

… I admit that it could be normal depending if you had a recent storm that was passing with some other conditions as well….but 25 isn't a "typical pressure" without at least some looking into….

 

[Maol]

@ M Jager How are you getting your pressure, the nearest station, or your own instrument? Just saying that your 26.45 seems really low. If it is your own instrument what is the nearest station's reading?

Did you return the scope to optical/manufacturer's zero before you set out dialing these in? I think you said you 'Boxed' it and it was good and returned to zero. How did you do your box test?

Your Delta is large and thinking it maybe more than one issue.

First I would try some Hornady or what ever else you know well. If the same thing happens I would start over with scope at 100 as has been suggested to go to find the flaws. Once you get it figured out you can go back to what ever zero you want.

 

[Mikecr]

I read "Elevation 3365, pressure 26.45,"
26.45 is standard pressure for altitude of 3365'ASL. It is referred to as 'station' or 'absolute' pressure.
His Kestrel displayed that altitude based on it's measured pressure.
I was wondering how this info was entered in his ballistic software.

If you would expect 29.92"Hg at 3365'ASL, that would be 'SL adjusted' pressure.
A Kestrel provides this as well, and you can use it as long as your software is aware of it.

 

[Maol]

Interesting. I enter values manually. We are at 5600' Nearest station at 5350' currently is:

 

[Doom2]

Interesting. I enter values manually. We are at 5600' Nearest station at 5350' currently is:

For general information in this discussion, the 30.12" HgA pressure is station pressure corrected to sea level (barometric pressure). In a ballistic calculator you would need to enter this as corrected pressure and also enter the altitude for the program to use to calculate air density.

 

[Maol]

For general information in this discussion, the 30.12" HgA pressure is station pressure corrected to sea level (barometric pressure). In a ballistic calculator you would need to enter this as corrected pressure and also enter the altitude for the program to use to calculate air density.

Have been just tweaking BC without issue.

BTW Shooter has pressure input type as a operator selection in settings. Not had a problem using it, but I get your point. Big difference.

 

[StanleyActual]

Have been just tweaking BC without issue.

BTW Shooter has pressure input type as a operator selection in settings. Not had a problem using it, but I get your point. Big difference.

i had to use a muzzle velocity of 2775 in AB and Srelok to get his 600 yd dope to line up, but then you gotta change his BC from .311 to like .450 to get his 1k dope where it needs to be.. that's not right

I'd be curious to see how a different factory ammo lines up

 

[Doom2]

To clear up some misconceptions, the chart below list the ICAO standard pressure at altitude based on 29.92 in HgA/14.696PSIA. In lieu of actual data, if you don't know pressure but do know altitude you can use the number from the chart. Actual station pressure will be close to that given in the chart.

Weathermen used to report pressure as barometric pressure (sea level) but over the years have gone to referring to barometric pressure as just pressure.

Most cell phones are capable of measuring actual station pressure. There is an app called "Barometer" that can be used to access this data.

 

[Doom2]

To the original issue, if the OP actually zeros at 255 yds, then zero at 100 yds and reverify the Dope. Trying to zero at 255 yds is quite a task as the groups open up some and introduce a larger error. Ultimately its the Dope that matters since it includes all of the effects that affect the flight of the bullet.

Ultimately, to true a ballistic app usually requires two separate sets of input data, the first is run with a ballistic coef as published, and varying muzzle velocity to match dope to 600 yds. At this range BC has a very minor effect. For ranges greater than 600 yds the actual muzzle velocity is used and BC is adjusted to match dope. Depending on the application and accuracy required sometimes minor adjustment of BC and velocity can be used together to match dope.

Note that 600 yds is somewhat arbitrary, and can be changed depending on caliber and cartridge.

 

[Maol]

I have been using measured velocity and truing with BC. The next time I will tweak velocity some too. I try to keep my ammo at body temp as a constant. But velocities still vary a bit, Std Deviation is never zero. I need a Labradar probably.

 

[Maol]

In checking out folks' thoughts on the Magneto V3 vs Labradar on 6.8 forums the discussion turns to the same thing as here.

They are confirming the importance of enviormentals on BC and even each barrels' very large delta between them with the same load, & lot etc even at relatively normal distances.

For what its worth read #11 & #12.

MagnetoSpeed V3 Ballistic Chronograph

www.68forums.com

 

[M Jager]

To take out suspected variables, I will reshoot with a 100 yard zero and shoot some 162 eld x that have available. Hopefully on Wednesday of the weather cooperates