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Mile shot calculations

Andyt

Private
Minuteman
Feb 14, 2023
9
0
Missouri
Hello all. Finally burst into the world of shooting beyond 1000 yards and hopefully this is simple enough. I shot a mile for the first time the other day and mile and while I ended up hitting the target within 4 shots I still missed 1,2 and 3. 3-5 mph crosswind. The ballistic calculator I use and have used for years (which is spot on at 1000 yards and closer) was 14 moa off target at 1761 yards. I checked other ballistic calculators as well and they were all within 1 moa of the one I use. My question is what happened between 1000 and 1760 yards? How do I account for whatever change is happening? What is the equation/equations to hand figure bullet drop?
 
What cartridge, bullet, and MV? Lots of possibilities could be responsible.
 
I bet you’re using g1 for a g7 imnput or something fundamental like that. Don’t waste any more ammo till you figure it out.
 
That load will need to be trued closer to 1700 yrds ( I am not looking at my kestrel right this minute but I am sure 600 is way to short),600 will not give you accurate data.
 
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You are saying that 3 or more different ballistics calculators are giving you spot on (within 1 moa) solutions out to 1000, but all come up 14 moa off when going from 1000 to a mile?
 
Then why does is match up perfectly below 1000 yards?
Because the trajectory is nearly flat until 800 yards or more. I shoot that bullet at 2940 fps and DA 4000+. I’m 4 Mil to 800, 6 to 1000 and 15 (fifteen!) at 1760
 
That load will need to be trued closer to 1700 yrds ( I am not looking at my kestrel right this minute but I am sure 600 is way to short),600 will not give you accurate data.
Probably more like 1300-1500, but yes - much farther than 600. Still, he’s a whopping 4 mils off at 1760, and I don’t think truing is going to account for anywhere near that much (unless his measured MV is waaaay off). There has to be an error somewhere.
OP - what solution did your calculator give you, and what were the environmentals?
 
You are saying that 3 or more different ballistics calculators are giving you spot on (within 1 moa) solutions out to 1000, but all come up 14 moa off when going from 1000 to a mile?
If your on at close range and falling from your dope as you move further out....look at your bc. Mv on the short stuff, bc on the far end.
 
The answer my friend is that after 1500 yards a G7 curve is WAY off for a modern bullet that is NOT close enough to the Reference G7 bullet. If you true it at 1760 then you will be off at other distances and be even further off at 2000 yards.

So...the bullet is not close enough to the reference bullet to match along the curve the software calculates. You can match it at certain points with what people call 'truing' but you will quickly be off more at other spots. What you see is that the more BC in the real world matters....the more it affects the software that is trying to model that flight path.

What we need is another model for modern bullets. We can use a PDM or Personal Drag Model or a CDM...Custom Drag Model shot over a high powered Doppler Radar and that gets you much closer to the curve of what you need...since then the 'Reference Bullet' will be the one shot in your gun, with your powder load, with your muzzle velocity....

There used to be the magic wall at 800YDs where 308wins couldn't pass....now we removed that wall and pushed it to 1000yds....then we take modern rounds and we push past that....now at 1500yds we have another riddle that we must solve. You can go bigger and extend that wall out further....or learn more and push that wall out further with knowledge.

Those of us that live at a mile and past...have all walked this road and sometimes we get to the same place by taking different paths....but it is a lesson we all have to learn. Hopefully in the future I'll give the same speech to those trying to push past 2500yds.
 
OP, just post your actual data. All your inputs into your calculator (which one, screenshots please?) and we will tell you what doesn't add up.

Right now everybody is just guessing amongst the 2 dozen variables that may be awry.

Something is seriously off kilter, and we need to identify exactly what it is.

Till we have the inputs, we're all just wasting time. At least we're not wasting ammo - but if you keep at it, w/o identifying the problem, that's what you will be doing
 
If you're going to play the long game, you might as well just pony up for the kestrel. My calculations on g7 inputs were 2 mils off from the kestrel predictions at 2grand. The kestrel was so damn close it's stupid.....but it only works based on what you tell it are facts....so, ENSURE the tall target test results transfer to your solver and nail the mv/environmental in the solver and let it work.
 
If you're going to play the long game, you might as well just pony up for the kestrel. My calculations on g7 inputs were 2 mils off from the kestrel predictions at 2grand. The kestrel was so damn close it's stupid.....but it only works based on what you tell it are facts....so, ENSURE the tall target test results transfer to your solver and nail the mv/environmental in the solver and let it work.
The guys whose range we were at had one and he was way closer to what it actually was vs our calculators. I thought it was because he had trued his rifle at that range with that device.
 
I’m not trying to be difficult and I am very green to ELR. So if I sound like an idiot it’s probably because I truly do not know. But heres the calculators that I use. Revic and jbm are my usual go to. The third one is a random one I used just to see. All three call for 69ish moa. Actual hits were 82 moa. 20 degree day 5-6 mph wind coming from 7-8 o’clock. I think I was holding 6 moa for wind but don’t really remember bc I didn’t write that down.

338 lapua, 285 gn eld-m, chrono avg 2741 fps,
2CC0EFD0-587C-4F52-B865-0385B13D5CD1.png

0321F291-D5FF-4DD8-BCE2-96BCFA987A9B.png


86E6AC2A-14CA-42FD-A9E1-7670C93A9F52.png

70D72015-EC5C-471E-BB89-5285FCADA08C.png

78FA4322-77FB-4913-ADE4-4B52A01F869B.png
 
Probably more like 1300-1500, but yes - much farther than 600. Still, he’s a whopping 4 mils off at 1760, and I don’t think truing is going to account for anywhere near that much (unless his measured MV is waaaay off). There has to be an error somewhere.
OP - what solution did your calculator give you, and what were the environmentals?
Posted some screen shots and enviro
 
I can't find the error. What are the odds your MV is actually 2541 fps? That'd do it but also not lining up at 1000 yards.
Unless that bullet is tumbling once it goes trans? but that doesn't happen consistently enough for reliable hits at a mile.

@secondofangle2 looks correct to me, G7 OF .417 and G1 .829 seems weird to bounce around like that but what ever.
 
If you use .8 as the g7 instead of .4, the difference is 15 MOA low at 1760

And part of his problem is that that calculator is a POS and not intuitive. No wonder a Newb gets lost in that mess of inputs
 
There's all kinds of inconsistencies in these numbers...not sure what I'm looking at.
1676480983371.png
 
If you use .8 as the g7 instead of .4, the difference is 15 MOA low at 1760

And part of his problem is that that calculator is a POS and not intuitive. No wonder a Newb gets lost in that mess of inputs
Ya but that doesn't account for his actual dope being 82 moa.

@ma smith Ya his numbers a whacked but those aren't going to equate the error he is talking about, unless there is another one some where.
 
Oh yeah I see you’re right. He should be about 65 MOA for that shot. But we did find the problem. His ballistic calculator is a POS and not user friendly. Time to get TRASOL (if he has iOS). Or AB.
 
That’s my hypothesis. His screenshots show both g1&g7. It just so happens if you put in .81 and call it the g7 BC the error is 15 MOA almost exactly the reported error

Plus, there are few other input errors that would cause an output error that large.

So the first order of business is to unfuck the BCs and see what the output is then.
 
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Ya if his memory is just off and is only remembering 14moa up from calculation and is adding that to what his calc is showing now.
How ever if his actual dope was 82 MOA the only realistic way I can come up with that is his velocity is way off.
 
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Yeah, but to get a come up of 82 MOA with that gun even with the 15 MOA error means his velocity is awful slow and I think he claimed earlier that it was adequately measured and came out right where one would expect the bullet
 
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Yeah, I was going to ask that too, what scope are you running?. However, even if you had 2% error in his scope tracking, which would be horrendous, that would only explain 1.6 minute of angle if his total come up with 80. Less if it’s come up with less than that. Honestly, scope tracking only helps for very very fine-tuning of loads beyond 2000 yards.
 
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Also if OP doesn't have a kestrel / CDM but is shooting Hornday bullets,
what about getting the poor mans custom drag curve from 4DOF?
 
Also if OP doesn't have a kestrel / CDM but is shooting Hornday bullets,
what about getting the poor mans custom drag curve from 4DOF?
Even it was within 1 MOA of everything else I looked at. IMO the diagnosis of swapping the BC types without changing the value is correct.
 
I’ll reiterate that it seems like something is going on with the scope or you’re somehow miscounting what your dialing. 84 MOa is like 25 mils. That’s a crazy number unless you’re running very slow. Old thread but here’s a sample of what people are dialing(were dialing in 2014 lol) at a mile. All are really close to 17 mils or 60 moa. Sure yours will be different but that’s wildly different.
https://www.snipershide.com/shooting/threads/338-lapua-to-a-mile-dope.210560/

What scope are you running?
 
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