Ballistic calculators disagree with my actual elevation amounts - help please!

[DocRDS]

1G acceleration is 32 feet per second per second. So 0.118s should equal a 3.7ft drop (assuming linear acceleration and that terminal velocity hasn't been reached).

OK, thanks for the advice, appreciated

You're over thinking. I'm an experimental scientist myself and I can tell you that reality and theory don't often match at the beginning. You want DATA. Our data suggests 0.5 mils 1.8 MOA for a 100 yard zero at 200 yards. (for instances your line of sight isn't parallel to the ground so you are actually shooting slightly "up" aka your scope is aimed slightly down) so the bullet "rises" compared to the ground a few inches but is acutally always falling from line of sight. At this level of precision/calculation details matter.)

And there is a huge amount of data that says your drop should be 0.5 mils at 200 or very close (as 200 yards isn't enough time to see variance in BC, MV. Don't try and do the theory of what it should be. We've measured it. We KNOW what is SHOULD be.

Even at 1000 yards, if you come in and say my dope is 4 Mils, even though the range of dope is larger for 1000 yards, we know something is wrong as you should be between 7 and 10 mills. All of our rifles shoot in that range (wanting for the idiot shooting a 33XC at 3200 FPS). You are shooting a standard 6.5 Creed. between 2700 and 2900 fps. We know roughly what your dope should be. If it isn't there are 2 solutions. (1) Something you are doing is wrong. (2) All of us are wrong.

Thus I am assuming #1.

In god we trust, all others bring data. Its a learning process, but too often I see people caught up in minutea. Practice practice practice your fundamentals at 100, 200, 400 yards (or similar) and get your DATA. If your data is outside the trend, something is off.

 

[Long Range 338]

Some great advice here but without seeing your inputs (screenshots of your data) it’s all just shots in the dark.

Anytime your 200 yard adjustment is 0.0 moa adjustment, I would call that a 200 yard zero…

 

[GrahamC]

You're over thinking. I'm an experimental scientist myself and I can tell you that reality and theory don't often match at the beginning. You want DATA. Our data suggests 0.5 mils 1.8 MOA for a 100 yard zero at 200 yards. (for instances your line of sight isn't parallel to the ground so you are actually shooting slightly "up" aka your scope is aimed slightly down) so the bullet "rises" compared to the ground a few inches but is acutally always falling from line of sight. At this level of precision/calculation details matter.)

And there is a huge amount of data that says your drop should be 0.5 mils at 200 or very close (as 200 yards isn't enough time to see variance in BC, MV. Don't try and do the theory of what it should be. We've measured it. We KNOW what is SHOULD be.

Even at 1000 yards, if you come in and say my dope is 4 Mils, even though the range of dope is larger for 1000 yards, we know something is wrong as you should be between 7 and 10 mills. All of our rifles shoot in that range (wanting for the idiot shooting a 33XC at 3200 FPS). You are shooting a standard 6.5 Creed. between 2700 and 2900 fps. We know roughly what your dope should be. If it isn't there are 2 solutions. (1) Something you are doing is wrong. (2) All of us are wrong.

Thus I am assuming #1.

In god we trust, all others bring data. Its a learning process, but too often I see people caught up in minutea. Practice practice practice your fundamentals at 100, 200, 400 yards (or similar) and get your DATA. If your data is outside the trend, something is off.

Not disagreeing that it's likely #1. However you say 1.8MOA, this is what Hornady 4DOF suggests:

 

[Partsunavailable]

Doc probably figured a more standard 1.5" sight height vs. your 2.5.

 

[Long Range 338]

I've replicated your inputs on my app and get the same results. I did have to turn of earth based effects and manually zero out azimuth as well to mimic your results. At 300 yards it shows 3.66 MOA which would be reasonable (almost exactly 1 mil).

It seems may have another type of error, not a ballistic solver error. A tall target test would be my first thing to test.

 

[Baron23]

No offense, you aren't there yet. The variations in BC are minute compared to getting your dope right.

Your "drop" at 200 yards should be approximately 0.5 mils or 1.8 MOA assuming your 100 yard zero is correct. Part of shooting is consistensy and it is entirely possible that yuo are seeing inconsistent positioning with your rifle as you move to different distances. That is FAR more likely than seeing variations in BC.

Master the basics first.

Can you keep 1 MOA shot to shot at 100. (No? Practice/Class)
Can you keep 1MOA shot to shot at 200....
300
500
etc...

The farther out you go the more "stuff" you have to contend with. (Wind, BC/Variation, Terrain) If your dope is not roughly 0.5/1.8 (it will vary based on your MV, sight height) at 200 after a 100 yard zero, its YOU. There is almost 0 other "stuff" at 200.

Put away your app for now.
Zero at 100.
Dial 0.5Mils or 1.8 MOA
Shoot at 200. Adjust. if you are more than 3 clicks either way off vertically something is WRONG.

Once you get that sorted get the worksheet here:

Advanced Marksmanship - My "Weaponized Math" now called "GRAVITY BALLISTICS". NEW Worksheet Attached.

SIMPLE * Could not be more effective or efficient Move from 200 yards to 1000 yards with less than a box of ammo. * Needs NO INPUTS - Just your DATA at 200 yards to get started. Mil or MOA. * Doesn't care what your M/V is... * Doesn't care what your bullet weighs or what your BC is... *...

www.snipershide.com

Run through the worksheet. (aka shoot dope to 1k)

Then get your ballistic app out and adjust the MV and BC until it predicts what you measured it the worksheet. It may not be perfect, some high, some low, but get em as close as possible.

Now you trust your ballistics app with VERIFIED data.

Ballistics App=Model. Models need to be tuned.

Almost all modern rifles run approximately 2750 fps, for a 100 yard zero that 0.5 mils/1.8 MOA drop at 200 (there is basically zero BC effect at 200 yards, normally to adjust your BC you look at 800+ dope--depends on person, rough guide, but 200 is all MV). That's the point of gravity ballistics. As you go farther and farther out, your data will get adjusted, but its a general trend of gravity. So if you have to dial DOWN (aka shooting high at 200) something is VERY VERY wrong if you have a 100 yard zero.

Maybe I missed that he has a very slow gun/low MV, but .5 at 200 is high IME. .4 and even .3 with fast loads would be what I’d start with if I was taking a shot in the dark at 200 yd come up.

 

[DocRDS]

Its an estimate. 1.3 MOA is fine. And since I am a "mil" guy 3 clicks is 0.3 mils which is 1MOA (4 clicks--MOA generally has smaller divisions). Doesn't matter which one you use. Point being you better be going UP at 200 and not DOWN.

Bury that calculator and GO SHOOT IT.

Use the gravity ballistics worksheet. THe point of the estimate is to get you on the paper and then you refine it. Point being it should be between 1-2 MOA. You don't care what your calculator says until the END.

Then go to 300. SHOOT IT (use the worksheet to "guess" your dope)

Then when you've got all your data look for outliers. Look at the change at each 100 yards. Does it get bigger? (it better!) That's your first check. Every 100 yards the bullet is accelerating "down" due to gravity. so 200-100 yard dope < 300 - 200 yard dope and so forth.

Then come back to the calculator and play with the MV and BC/FormFactor until it matches your MEASURED elevation as close as possible. It may be off 1/4 moa here or there (or maybe even 1/2). You want the "best" fit. Use all 10 data points 100-1000. If you can't get 10, get as many as possible.

 

[GrahamC]

Its an estimate. 1.3 MOA is fine. And since I am a "mil" guy 3 clicks is 0.3 mils which is 1MOA (4 clicks--MOA generally has smaller divisions). Doesn't matter which one you use. Point being you better be going UP at 200 and not DOWN.

Bury that calculator and GO SHOOT IT.

Use the gravity ballistics worksheet. THe point of the estimate is to get you on the paper and then you refine it. Point being it should be between 1-2 MOA. You don't care what your calculator says until the END.

Then go to 300. SHOOT IT (use the worksheet to "guess" your dope)

Then when you've got all your data look for outliers. Look at the change at each 100 yards. Does it get bigger? (it better!) That's your first check. Every 100 yards the bullet is accelerating "down" due to gravity. so 200-100 yard dope < 300 - 200 yard dope and so forth.

Then come back to the calculator and play with the MV and BC/FormFactor until it matches your MEASURED elevation as close as possible. It may be off 1/4 moa here or there (or maybe even 1/2). You want the "best" fit. Use all 10 data points 100-1000. If you can't get 10, get as many as possible.

Sound advice, thanks.

 

[GrahamC]

So I shot at 300 yards today as the 100 and 200 yard ranges weren't available.

4DOF suggested 3.66MOA come up. I had to dial 3.0MOA in the end for this result.

That's only a 2 inch difference between calculator suggested vs. actual which suggests that my 100 yard zero is actually close, but doesn't explain why I had to dial -0.25MOA at 200 yards...

Windage was a bit off as it was quite gusty today.

Will go back and re-check both 100 and 200 yard figures when I get a chance.

 

[Partsunavailable]

So I shot at 300 yards today as the 100 and 200 yard ranges weren't available.

4DOF suggested 3.66MOA come up. I had to dial 3.0MOA in the end for this result.

View attachment 8472751

That's only a 2 inch difference between calculator suggested vs. actual which suggests that my 100 yard zero is actually close, but doesn't explain why I had to dial -0.25MOA at 200 yards...

Windage was a bit off as it was quite gusty today.

Will go back and re-check both 100 and 200 yard figures when I get a chance.

Where does that velocity come from? Because if its at the target, you are only 16 fps slower than last week at 100 yards. That doesn't make sense either. Or do all the electronic targets use the 100 yard velocity?

 

[LuckyLuke80]

So I zeroed at 100 yards and then shot another 60+ rounds at target. Example of my results below, I think after about 40 rounds. What potential issues could I have with my 100 yard zero then, so that I have some idea of what to consider and eliminate?

View attachment 8468696

Your group center is showing close to half moa high if this depiction is accurate. I would say that’s a big part of the problem.

 

[LuckyLuke80]

I would also add that Gravity Ballistics doesn’t have a “try” number for 200 yards. Basically 200 yards isn’t going to tell you much that 100 isn’t already telling you.

 

[Ronws]

I would also add that Gravity Ballistics doesn’t have a “try” number for 200 yards. Basically 200 yards isn’t going to tell you much that 100 isn’t already telling you.

That is what I have learned and any honest app is going to tell you that you cannot really true the calculator all that well until you get past 200 yards or something with enough flight time and vulnerable to the wind.

 

[LuckyLuke80]

My opinion-people get too wrapped around the axle about apps and gadgets and don’t spend enough time actually shooting. That’s why I really like the gravity ballistics app. I took my 308 out and was messing with a bunch of different ballistic apps. Then I deleted all of them and went to the range. Worked zero, then used the gravity numbers that @EnoughSaid has come up with. Within 30 minutes I was getting hits out to 700 yards. No, I wasn’t necessarily shooting bullseyes out at 700, but I was getting good hits on target.

 

[Ronws]

My opinion-people get too wrapped around the axle about apps and gadgets and don’t spend enough time actually shooting. That’s why I really like the gravity ballistics app. I took my 308 out and was messing with a bunch of different ballistic apps. Then I deleted all of them and went to the range. Worked zero, then used the gravity numbers that @EnoughSaid has come up with. Within 30 minutes I was getting hits out to 700 yards. No, I wasn’t necessarily shooting bullseyes out at 700, but I was getting good hits on target.

This reminds me of how the job of the rifle is so important.

One may not take out the bull's eye but a hit in the zone of choice is still a hit. The author of another favorite book of mine on long range shooting is Ryan Cleckner. Formerly, he was a sniper team leader in the Rangers 1/75 for a number of deployments in the GWOT.

He carried a .300 Win Mag in service. He described his shooting there as "tactical." He was never going to pierce an earlobe or take the x in a target paper. The way the .300 WM performed, he could dial elevation for distance and then hold left or right edge of an IPSC shaped target into the wind and get a hit in that IPSC zone. Which is what the job required.

Even today, he admits he would probably do lousy at a PRS or most precision rifle contests. But give him a rifle that can be verified as 1 MOA and he will hit somewhere in a 10.5 inch area at 1,000 yards. That is, he can shoot 1 MOA as a system.

I like how gravity doesn't carry about scope height over bore. Once you have an actual zero, the only constant factor is gravity.

 

[GrahamC]

Where does that velocity come from? Because if its at the target, you are only 16 fps slower than last week at 100 yards. That doesn't make sense either. Or do all the electronic targets use the 100 yard velocity?

It's calculated by the Shotmarker electronic target although I've no idea how it generates the velocity or whether it varies based on distance.

Garmin chrono showed MV from the AI with a low of 2655fps and high of 2721 with an average of 2685 which I used in 4DOF.

Out of the Ruger I had a single round register 3051fps which was 453fps faster than the slowest! 147gr ELD-Match.

 

[GrahamC]

My opinion-people get too wrapped around the axle about apps and gadgets and don’t spend enough time actually shooting. That’s why I really like the gravity ballistics app. I took my 308 out and was messing with a bunch of different ballistic apps. Then I deleted all of them and went to the range. Worked zero, then used the gravity numbers that @EnoughSaid has come up with. Within 30 minutes I was getting hits out to 700 yards. No, I wasn’t necessarily shooting bullseyes out at 700, but I was getting good hits on target.

Yes I agree that it's possible to get too fixated on apps and gadgets. My original question was how to determine an elevation for 1000 yards at the range when I've not yet shot past 600 yards given that the calculator doesn't seem to agree with actual elevation.

 

[GrahamC]

This reminds me of how the job of the rifle is so important.

One may not take out the bull's eye but a hit in the zone of choice is still a hit. The author of another favorite book of mine on long range shooting is Ryan Cleckner. Formerly, he was a sniper team leader in the Rangers 1/75 for a number of deployments in the GWOT.

He carried a .300 Win Mag in service. He described his shooting there as "tactical." He was never going to pierce an earlobe or take the x in a target paper. The way the .300 WM performed, he could dial elevation for distance and then hold left or right edge of an IPSC shaped target into the wind and get a hit in that IPSC zone. Which is what the job required.

Even today, he admits he would probably do lousy at a PRS or most precision rifle contests. But give him a rifle that can be verified as 1 MOA and he will hit somewhere in a 10.5 inch area at 1,000 yards. That is, he can shoot 1 MOA as a system.

I like how gravity doesn't carry about scope height over bore. Once you have an actual zero, the only constant factor is gravity.

Yes I've read Long Range Shooting, an interesting and well written book. Of course his use was quite different from my target shooting Fair play to the guy, I wouldn't want to do what he did.

 

[JerkyFreak]

It's calculated by the Shotmarker electronic target although I've no idea how it generates the velocity or whether it varies based on distance.

Garmin chrono showed MV from the AI with a low of 2655fps and high of 2721 with an average of 2685 which I used in 4DOF.

Out of the Ruger I had a single round register 3051fps which was 453fps faster than the slowest! 147gr ELD-Match.

It is calculated by the Shotmarker by measuring the passage of the shockwave past the two microphones in each sensor and then averaged over the 4 sensors.

Might not be 100% correct, but close enough to say that it is the average velocity of the bullets at the target.

 

[GrahamC]

It is calculated by the Shotmarker by measuring the passage of the shockwave past the two microphones in each sensor and then averaged over the 4 sensors.

Might not be 100% correct, but close enough to say that it is the average velocity of the bullets at the target.

I think three sensors are required to accurately triangulate the position with the fourth for redundancy.

That is indeed how it determines point of impact due to the time deltas to each microphone but not clear how that helps with determining velocity? Clearly I don't know the tech well enough. It would be interesting to know the level of claimed accuracy.

 

[GrahamC]

Hornady BC predicts a significantly lower target velocity than Shotmarker using the same inputs from yesterday, 2451fps (Shotmarker) vs 2305.

 

[JerkyFreak]

Every sensor has two microphones around 12 inches apart; the front microphone and rear microphone. This distance is far enough apart to use the sonic wave passing to caculate bullet velocity to be accurate to +-20ft/s. This is done as a data and sensor quality check.

The four front microphones work together to get a shot position in the front plane. The rear microphones work together to get the shot position in the rear plane. These two positions are then used to plot the angle that the bullet went through the target. This angle is used to differentiate cross-fired rounds.

Now, if your shot positions are correct, the velocity through the target must also be correct. If not, contact Adam MacDonald for fault-finding.

 

[BrassGoblin03]

My god yall know how to complicate things

 

[hlee]

My god yall know how to complicate things

If you like this, hit up the reloading section…

 

[BrassGoblin03]

If you like this, hit up the reloading section…

People always trying to reinvent the wheel instead of just driving the car.

 

[LuckyLuke80]

People always trying to reinvent the wheel instead of just driving the car.

Kind of why I made the comment I did about gravity ballistics. Not trying to be a pompous idiot, but getting all wrapped up in bc, and how a chrono works isn’t going to solve why a zero is wrong and a guy can’t get data beyond 600 yards.

 

[BrassGoblin03]

Kind of why I made the comment I did about gravity ballistics. Not trying to be a pompous idiot, but getting all wrapped up in bc, and how a chrono works isn’t going to solve why a zero is wrong and a guy can’t get data beyond 600 yards.

I agree 100%

 

[Mumzergadol]

Did this ever get figured out?

 

[GrahamC]

Thanks for asking, I did!

I connected a Kestrel to the Hornady app and the elevation figure for first time shooting at 600 yards was within a few inches of dead centre. So accurate atmospherics seems critical.

I also borrowed a LRF and found that the 600 yard distance was almost spot on at 601.7 yards.

What I can't explain is the inconsistency of my 200 yard elevation. I will likely go back and check 100 and 200 yard zeros but currently am happy shooting at 600 yards - got a 7 round 0.65MOA grouping recently which I was pleased with.

 

[Mumzergadol]

it was driving me nuts. i still think the 200 yard zero is undeniably suspicious. let us know what you find

 

[Enough Said]

This is a perfect example of my teaching point; ERRORS ARE CUMULATIVE.

Until you start eliminating them, one by one, to include hammer-forging your fundamentals, you will not reach predictable, repeatable precision and accuracy.

 

[GrahamC]

This is a perfect example of my teaching point; ERRORS ARE CUMULATIVE.

Until you start eliminating them, one by one, to include hammer-forging your fundamentals, you will not reach predictable, repeatable precision and accuracy.

True. Although none of the ballistic calculators I can across made it particularly clear that to make them work effectively you'd need at least a chronograph and a weather meter (and ideally a LRF). That could be naivety on my part but I'm sure I'm not the only one...

 

[Baron23]

True. Although none of the ballistic calculators I can across made it particularly clear that to make them work effectively you'd need at least a chronograph and a weather meter (and ideally a LRF). That could be naivety on my part but I'm sure I'm not the only one...

In that case, sadly you don’t know anything about ballistics.

You, and others you alluded to, need to educate yourself on inputs to a ballistic solution. Nobody is born with this knowledge and all needed to learn about it in one way or another.

As far as the calculators making these data input requirements clear or not, the fact that there are clearly marked data input fields should actually be a give away that these data are required.

 

[Enough Said]

True. Although none of the ballistic calculators I can across made it particularly clear that to make them work effectively you'd need at least a chronograph and a weather meter (and ideally a LRF). That could be naivety on my part but I'm sure I'm not the only one...

Chrono needed only if you are a reloader. That would be to measure Standard Deviation once a promising load reveals itself. M/V can be determined easily by shooting a mid-range small target and backing into it using a solver, but you will need the equipment parameters required by the solver. M/V can be a placeholder only, like 2,750 for 6.5 CM, and then true the solver until the solver M/V matches the actual hit.

Weather meter will be required equipment of any long range shooter, unfortunately, but NOT one that includes a solver.

Enjoy the journey, brother.

 

[GrahamC]

In that case, sadly you don’t know anything about ballistics.

You, and others you alluded to, need to educate yourself on inputs to a ballistic solution. Nobody is born with this knowledge and all needed to learn about it in one way or another.

As far as the calculators making these data input requirements clear or not, the fact that there are clearly marked data input fields should actually be a give away that these data are required.

I think it should be obvious that if I knew a lot about ballistics I wouldn't be here asking in the first place.

Were you born an expert ballistician or at some point did you have to also learn the basics? I went and read Applied Ballistics for Long Range Shooting by Bryan Litz.

Thanks for your erudite contribution to the thread

 

[GrahamC]

Chrono needed only if you are a reloader. That would be to measure Standard Deviation once a promising load reveals itself. M/V can be determined easily by shooting a mid-range small target and backing into it using a solver, but you will need the equipment parameters required by the solver. M/V can be a placeholder only, like 2,750 for 6.5 CM, and then true the solver until the solver M/V matches the actual hit.

Weather meter will be required equipment of any long range shooter, unfortunately, but NOT one that includes a solver.

Enjoy the journey, brother.

Thanks, useful advice.

I'm not a reloader but can see why people are when I've seen a MV range between 2,500 and 3,000fps with ELDM ammo.

 

[Ronws]

Chrono needed only if you are a reloader. That would be to measure Standard Deviation once a promising load reveals itself. M/V can be determined easily by shooting a mid-range small target and backing into it using a solver, but you will need the equipment parameters required by the solver. M/V can be a placeholder only, like 2,750 for 6.5 CM, and then true the solver until the solver M/V matches the actual hit.

Weather meter will be required equipment of any long range shooter, unfortunately, but NOT one that includes a solver.

Enjoy the journey, brother.

That's one of the things I like about Strelok Pro. You can start out with the known or supposedly known MV. But if you have to adjust elevation to get PoI, it will take that adjustment and come up with an adjusted MV and ask if you want to use that.

 

[Baron23]

I think it should be obvious that if I knew a lot about ballistics I wouldn't be here asking in the first place.

Were you born an expert ballistician or at some point did you have to also learn the basics? I went and read Applied Ballistics for Long Range Shooting by Bryan Litz.

Thanks for your erudite contribution to the thread

Maybe you missed the part of

Nobody is born with this knowledge and all needed to learn about it in one way or another.

Good luck to you.

 

[Mumzergadol]

Chrono needed only if you are a reloader. That would be to measure Standard Deviation once a promising load reveals itself. M/V can be determined easily by shooting a mid-range small target and backing into it using a solver, but you will need the equipment parameters required by the solver. M/V can be a placeholder only, like 2,750 for 6.5 CM, and then true the solver until the solver M/V matches the actual hit.

Weather meter will be required equipment of any long range shooter, unfortunately, but NOT one that includes a solver.

Enjoy the journey, brother.

This is the right answer. If you are shooting factory ammo, the precise speed doesn't matter. Use the estimate from the box add or subject 25 fps per inch of barrel other than 24" and stop worrying about the chrono.

Go shoot it. The bullets and targets tell the truth. All the basic solvers... I'm a strelok guy... Will allow you to back into the effective mv out to 600. Beyond 600 you'll find yourself fiddling with bc.

You can do all this with a phone app and a 90 dollar weatherflow meter.

None of it will yield satisfying results unless you are bang on at 100. If not, you'll be chasing ghosts. They may be consistent ghosts, but you'll still be chasing.

 

[GrahamC]

Maybe you missed the part of


Good luck to you.

You're right, although I read that part I became focused with what I thought was an overly blunt comment:

In that case, sadly you don’t know anything about ballistics.

You, and others you alluded to, need to educate yourself

My apologies for my barbed response.

 

[Baron23]

You're right, although I read that part I became focused with what I thought was an overly blunt comment:

In that case, sadly you don’t know anything about ballistics.

You, and others you alluded to, need to educate yourself

My apologies for my barbed response.

Well, it was a bit overly blunt. My apologies for that but it is the internet and, as is often the case, not a lot of time was given to wording or ensuring that the emotional tone is properly conveyed.

But, in general the point does still stand. There is tons of info out there on ballistic calculations and the environmental data needed to generate density altitude which, along with drag coefficient and time of flight, is the key determinant of the elevation solution.

On Hornady’s 4DOF website, they have instructions that goes thru the data needed and even have a technical doc.

https://static.hornady.media/site/hornady/files/ballistic/hornady-4dof-technical-paper-v2.pdf

And Hornady (and others) has vid tutorial that also goes thru the solver…how to use some of the data that is needed

yourube 4dof tutorial video - Google Search

Best of luck. Cheers

 

[Taylorbok]

Well, it was a bit overly blunt. My apologies for that but it is the internet and, as is often the case, not a lot of time was given to wording or ensuring that the emotional tone is properly conveyed.

But, in general the point does still stand. There is tons of info out there on ballistic calculations and the environmental data needed to generate density altitude which, along with drag coefficient and time of flight, is the key determinant of the elevation solution.

On Hornady’s 4DOF website, they have instructions that goes thru the data needed and even have a technical doc.

https://static.hornady.media/site/hornady/files/ballistic/hornady-4dof-technical-paper-v2.pdf

And Hornady (and others) has vid tutorial that also goes thru the solver…how to use some of the data that is needed

yourube 4dof tutorial video - Google Search

Best of luck. Cheers

The more you get familiar with calculators and cartridges you can basically fudge every number to get you super ass close out to 1000 yards.

Doesn’t mean you should but when someone shows up to the range with no dope/data it’s pretty easy to whip up a profile and get them on target

 

[GrahamC]

Well, it was a bit overly blunt. My apologies for that but it is the internet and, as is often the case, not a lot of time was given to wording or ensuring that the emotional tone is properly conveyed.

But, in general the point does still stand. There is tons of info out there on ballistic calculations and the environmental data needed to generate density altitude which, along with drag coefficient and time of flight, is the key determinant of the elevation solution.

On Hornady’s 4DOF website, they have instructions that goes thru the data needed and even have a technical doc.

https://static.hornady.media/site/hornady/files/ballistic/hornady-4dof-technical-paper-v2.pdf

And Hornady (and others) has vid tutorial that also goes thru the solver…how to use some of the data that is needed

yourube 4dof tutorial video - Google Search

Best of luck. Cheers

Yes, your point is valid and when I posted my original comment I was at the start of that learning curve.

BCs introduce lots of new things, many of which at medium range you don't need to consider (coriolis effect, spin drift, aerodynamic jump etc) as well as a host of inputs without really highlighting the most critical. Bryan Litz's book does explain that.

BCs give you a very accurate result but that's based on the accuracy of the inputs - garbage in, garbage out. Prior to having a chrono I used Hornady's published MV figure but that assumes a specific barrel length (I have both 24" and 26"). For environmental conditions I used weather forecast for temperature and barometric pressure. These are better than nothing but not accurate and hence the variation.

Thanks for the comments.

 

[GrahamC]

The more you get familiar with calculators and cartridges you can basically fudge every number to get you super ass close out to 1000 yards.

Doesn’t mean you should but when someone shows up to the range with no dope/data it’s pretty easy to whip up a profile and get them on target

That to me is the key point. If I have no dope at a specific distance, if a BC can get me on target refining is then way easier.

 

[Taylorbok]

That to me is the key point. If I have no dope at a specific distance, if a BC can get me on target refining is then way easier.

One stipulation is a good zero. Or atleast knowing where the zero is. As mentioned those issues will be magnified at distance. I’m still not sure if you figured out your issue or not

 

[vh20]

Skimming through, it doesn't sound like the BIG elephant in the room was ever addressed - having to dial down from 100 to 200. Shooting at 600 and being happy is nice, but there's a glaring error that still hasn't been addressed and it WILL re-surface and bite you when you get away from that 600 target.

Have you tried dialing your 100 yd zero (0.0 on the turret), shooting a group at 100 to confirm it's on, THEN shooting a group at 200 WITHOUT TOUCHING THE TURRET, leave it at 0.0? If your group at 200 isn't then somewhere between 1-2 MOA low there's an equipment problem assuming the shooter is solid. If needed, get a known solid shooter to shoot it again. You've got to solve this discrepancy before you're going to be able to progress.

If 0.0 at 200 DOES give you a group 1-2 MOA low, then dial in what you were having to dial before (-0.25 I believe it was?) to achieve a zero at 200. If the group returns to Zero at 200 instead of going 0.25 even lower, you have a scope tracking/mount problem.

 

[Enough Said]

All the BC or muzzle velocity in the world will do you no justice without removing shooter influence.
Shooter influence is eliminated through proper application of the fundamentals. And to be honest, it can never be removed. It's like a bias. Make your bias consistent.

Rifles don't fire themselves, we influence them. Consistent influence produces consistent result

You cannot acquire fundamentals by googling them. You need scrutiny and coaching to make your influence consistent.

When all comes together, we achieve predictable, repeatable precision and accuracy.

 

[GrahamC]

Responding to several comments here.

I haven't yet returned to 100/200 yards although I intend to. My suspicion is that my 100 yard zero wasn't 100% accurate which I suspect is the cause of the 200 yard discrepancy. It's either that or a kit set up although I did take a lot of care trying to level the scope using a gun vice and Wheeler scope level.

What is interesting is that my Vortex LRF paired with a Kestrel said that I needed a 13.0 MOA elevation at 600 yards. I dialled that and got this result.

The far left shot on the 2/3 ring was my cold bore sighter shot after which I applied windage. Inner bull is 7.8 inches so 1.3MOA at 600 yards. Given I'd never call myself an expert shot I was happy with this but will continue to work to tighten up my grouping.

 

[GrahamC]

This is the kit I was using today.

Accuracy International AT-X 6.5 Creedmoor, Vortex Razor Gen III, Accu-tac bipod, Alacris Fortis rear bag.

 

[GrahamC]

Skimming through, it doesn't sound like the BIG elephant in the room was ever addressed - having to dial down from 100 to 200. Shooting at 600 and being happy is nice, but there's a glaring error that still hasn't been addressed and it WILL re-surface and bite you when you get away from that 600 target.

Have you tried dialing your 100 yd zero (0.0 on the turret), shooting a group at 100 to confirm it's on, THEN shooting a group at 200 WITHOUT TOUCHING THE TURRET, leave it at 0.0? If your group at 200 isn't then somewhere between 1-2 MOA low there's an equipment problem assuming the shooter is solid. If needed, get a known solid shooter to shoot it again. You've got to solve this discrepancy before you're going to be able to progress.

If 0.0 at 200 DOES give you a group 1-2 MOA low, then dial in what you were having to dial before (-0.25 I believe it was?) to achieve a zero at 200. If the group returns to Zero at 200 instead of going 0.25 even lower, you have a scope tracking/mount problem.

That's a great suggestion which I'll try. UK weather is now getting to the crappy stage of the year; I will likely concentrate on my .22LR gallery shooting now (shooting position is covered and yeah, call me a wimp for not wanting to do all weather shooting ) and return to centrefire shooting in spring.