What can cause a bullet to impact higher, when moving back to 200 yards, from 100 yards?

[yo-yo]

I saw a somewhat similar thread on here about this, but I thought I would ask a more specific question about this.

I zero'd in at 100 yards about week ago, and I didn't move the turrets because we ran out of daylight. Yesterday, I was getting ready to move my turrets up, when my friend told me I would need to move it DOWN. I was confused, but he went on to explain this is the phenomenon he's always experienced when he shoots on this part of the property (with all his guns). I bet him he was wrong.

I took a few shots at 200 yards yesterday, and I shot about 5" high! WTF?! I thought I was zero'd well at 100 yards. I figure I my zero at 100 yards must be way off. We ran out of daylight again, so I couldn't do anymore to investigate.

I think the spot we are shooting 200 yards from might actually sit up another 6' in elevation...but that isn't going to make a big difference is it? Shooting angle would down a small small amount, but I doubt that could account for shooting 5" high at 200 yards, could it?

We didn't have the Kestrel working on either day of shooting, but it seemed a little windy on the day of shooting 100 yards, and yesterday it seemed very very calm. Similar temps.

Another friend showed up yesterday and I mentioned this to him. He went on to describe something else...This is something other people have talked about before too, which is that the bullet is still travelling up when it impacts the target. I am familiar with this discussion, though I don't think the bullet would still be travelling upward, away from the horizontal at 200 yards, unless I really messed up my 100 yard zero.

Is it possible to mess up a scope sight-in so badly, a bullet literally does not reach its peak elevation and begin to fall toward the horizontal, when impacting a target?

I'm lost on what could cause this, other than an improper zero at a shorter distance.

 

[db2000]

300 mag 2.5" high 100 yards, 3" high 200 yards? | General Hunting

I cannot explain this. 100 yards I am 2.5" high and 200 yards I am 3" high. Same gun, same bullets same day switched back and forth twice (100 then 200, back to 100 then 200 yards). How? Tikka 300 win mag, got a new muzzle break - first time shooting after it was installed. Remington corlokt...

www.monstermuleys.info

 

[yo-yo]

300 mag 2.5" high 100 yards, 3" high 200 yards? | General Hunting

I cannot explain this. 100 yards I am 2.5" high and 200 yards I am 3" high. Same gun, same bullets same day switched back and forth twice (100 then 200, back to 100 then 200 yards). How? Tikka 300 win mag, got a new muzzle break - first time shooting after it was installed. Remington corlokt...

www.monstermuleys.info

Yeah, I saw that, but I just can’t explain how my friends experience could occur over and over again, with different guns, and still have shots at 200 yards hit high. I was shocked myself. I can’t explain it, other than my 100 yard zero must be off.

 

[spife7980]

Usually it’s like 25 and 100 or 50 and 300 with the dual zero thing but I suppose it’s possible. Enter your data in a ballistic calculator and see its drop.

5” high at 200 from a 100yd zero is a lot though. What chambering are you shooting?

 

[CoryT]

Are your sights above the bore? If so, and you were actually on zero at 100 then the bullet will strike low at 200. So, you either were not zeroed, or you incorrectly set the elevation knob. Gravity is not just a good idea, it's the law.

 

[hlee]

Are your sights above the bore? If so, and you were actually on zero at 100 then the bullet will strike low at 200. So, you either were not zeroed, or you incorrectly set the elevation knob. Gravity is not just a good idea, it's the law.

Not exactly. Spife has it in his diagram. We typically use a 100 yard zero because; with typical cartridges and typical scope mounting, the line of sight is- more or less- tangent to the arc of the bullet path at 100 yards. This allows us to dial “up” for both very close and very distant targets. However, if your bullet trajectory and/or height over bore are non-typical, you can be in a situation where you have both a near and a far zero, and between these zeros bullets will impact above the line of sight.

That said, when relying on a ballistic calculator for “dope” it is very important that your zero is accurate and precise, as is your height over bore. If your “zero” is high and your height over bore is greater than what you feed the software, your bullets will impact higher than the software says they should.

 

[CoryT]

Not exactly. Spife has it in his diagram. We typically use a 100 yard zero because; with typical cartridges and typical scope mounting, the line of sight is- more or less- tangent to the arc of the bullet path at 100 yards. This allows us to dial “up” for both very close and very distant targets. However, if your bullet trajectory and/or height over bore are non-typical, you can be in a situation where you have both a near and a far zero, and between these zeros bullets will impact above the line of sight.

That said, when relying on a ballistic calculator for “dope” it is very important that your zero is accurate and precise, as is your height over bore. If your “zero” is high and your height over bore is greater than what you feed the software, your bullets will impact higher than the software says they should.

Absent a 5"+ high scope mount, if he is in fact zeroed at 100, it's low at 200. Yes, there are two zero points on a trajectory, but with conventional sights and cartridges, the near/far zero at 100 yards is at best 100 - 105. Caliber is not stated, nor is bore height, but a .308 with a factory type scope mount/base might be zeroed at 500 yards, and it would also be on zero at about 11 yards, the initial intersection. I await a ballistic chart showing an off the shelf configuration that would produce a 100 yard initial intersection and a 5" high 200 yard trajectory.

 

[hlee]

Absent a 5"+ high scope mount, if he is in fact zeroed at 100, it's low at 200. Yes, there are two zero points on a trajectory, but with conventional sights and cartridges, the near/far zero at 100 yards is at best 100 - 105. Caliber is not stated, nor is bore height, but a .308 with a factory type scope mount/base might be zeroed at 500 yards, and it would also be on zero at about 11 yards, the initial intersection. I await a ballistic chart showing an off the shelf configuration that would produce a 100 yard initial intersection and a 5" high 200 yard trajectory.

Idk. The “problem statement” has a bunch of holes that make me doubt the premise. And, I fully acknowledge that the most likely cause is a zero that is not zero. Perhaps it’s a pedantic point, but height over bore is a necessary variable.

 

[CoryT]

Idk. The “problem statement” has a bunch of holes that make me doubt the premise. And, I fully acknowledge that the most likely cause is a zero that is not zero. Perhaps it’s a pedantic point, but height over bore is a necessary variable.

True, but given the ranges and elevation, it would take a mount like that to cause the issue. If that were the case, I doubt the OP would be asking about it here.

 

[hlee]

True, but given the ranges and elevation, it would take a mount like that to cause the issue. If that were the case, I doubt the OP would be asking about it here.

Fuuuuuuuuuuuuuuck, have you seen the “Savage cage match” thread, or the “what’s the cheapest chassis I can get for a savage” thread, or the “I’m a ninja and need a rifle I can carry in a briefcase” thread? As a matter of fact, how new ARE you? Anymore, the slogan for SH should be “for questions too dumb for ar15.com…”

 

[misser]

shooting down hill ?

 

[Evintos]

I think the spot we are shooting 200 yards from might actually sit up another 6' in elevation...but that isn't going to make a big difference is it? Shooting angle would down a small small amount, but I doubt that could account for shooting 5" high at 200 yards, could it?

I'm lost on what could cause this, other than an improper zero at a shorter distance.

What's your actual angle compensated horizontal distance when you zeroed the rifle and when you shot the 200yd target?

Another 6' in elevation makes it seem like you were already shooting at an angle relative to the 100yd target.

Are we talkin 100yd and 200yd line of sight or horizontal?

Did you end up actually getting some weird battlesight zero effect?

 

[yo-yo]

Are your sights above the bore? If so, and you were actually on zero at 100 then the bullet will strike low at 200. So, you either were not zeroed, or you incorrectly set the elevation knob. Gravity is not just a good idea, it's the law.

Yes, my scope is above the bore. I haven't actually measured the height, but I'm using a ARC M-Brace mount that's their low mount (1.26") with a 34mm tube scope. I'm wondering if I simply zero'd wrong at 100 yards. I hit the bullseye directly and have a group of about 1/2", so I thought that might be good. Funny thing is...I didn't adjust the elevation knob...I left it alone because of the bet my buddy made me. I expected to shoot low by 1", but I shot high by 5".

 

[yo-yo]

View attachment 8491777

Usually it’s like 25 and 100 or 50 and 300 with the dual zero thing but I suppose it’s possible. Enter your data in a ballistic calculator and see its drop.

5” high at 200 from a 100yd zero is a lot though. What chambering are you shooting?

Ah, interesting. I didn't realize the dual zero could vary. I will input the data and see what I get.
I'm shooting a 6.5 Creedmoor and I was using a 120 gain Federal round with the chronograph showing 3076 ft/sec.

 

[spife7980]

Ah, interesting. I didn't realize it could vary. I will input the data and see what I get.
I'm shooting a 6.5 Creemoor and I was using a 120 gain Federal round with the chronograph showing 3076 ft/sec.

Hmmm, that shouldn’t be 5” high at 200 with any sight height combination. With the rings you mentioned above on a bolt gun you’ll be about 2.25” over

https://jbmballistics.com/cgi-bin/jbmtraj_simp-5.1.cgi

You’re certain that 100 is 100 and 200 is 200?

 

[yo-yo]

Hmmm, that shouldn’t be 5” high at 200 with any sight height combination. With the rings you mentioned above on a bolt gun you’ll be about 2.25” over

https://jbmballistics.com/cgi-bin/jbmtraj_simp-5.1.cgi

You’re certain that 100 is 100 and 200 is 200?

Hmmm...yeah, I was using the Hornady app, but it doesn't show as much information as yours. I'll look at this chart data a little closer, but both seem to show a plateau at 100 yards, and doesn't appear to have enough definition to show a dual cross-over the line of sight.

 

[Evintos]

Something is way off.

The only way he'd even get close to 5" high at 200 is with a zero distance of 18-19yds. If he had an 18yd zero, it'd mean his shooting position was 98.37yds above the 100yd target and shooting off the edge of a cliff at a 79.63 degree angle, or the other way around, shooting up towards a target on top of a cliff.

When it comes to shooting the 200yd target though, he'd only be aiming downhill at around a 31 degree angle. Angle compensated horizontal distance would be 170yd.

 

[misser]

some years back shooting a encore 10'' hand gun 762x39 125 gr out to 200 yd. gun zeroed at 100yd .there was elevation change of 20' . 2 targets one ontop of the other, aiming at top target center hitting top target center

 

[yo-yo]

Not exactly. Spife has it in his diagram. We typically use a 100 yard zero because; with typical cartridges and typical scope mounting, the line of sight is- more or less- tangent to the arc of the bullet path at 100 yards. This allows us to dial “up” for both very close and very distant targets. However, if your bullet trajectory and/or height over bore are non-typical, you can be in a situation where you have both a near and a far zero, and between these zeros bullets will impact above the line of sight.

That said, when relying on a ballistic calculator for “dope” it is very important that your zero is accurate and precise, as is your height over bore. If your “zero” is high and your height over bore is greater than what you feed the software, your bullets will impact higher than the software says they should.

The funny thing is...I didn't use the calculator for anything. I just sighted in the gun at 50 yards (the gun is new to me, and the scope is brand new). Moved to 100 yards, took some shots, and made some fine tuning adjustments - and hit the bullseye. I left it there and moved back another 100 yards, expecting to shoot low by about 1" if I didn't move the turret (calculator said to move up 0.34 mrads when moving to 200 yards). But, now I think about it...I wonder if I would shoot low by 2" (leaving the scope unadjusted at 200 yards), since the 0.36 mrads at 200 yards would be double that of 100 yards, right, and really be 2"??). Ugh. I haven't thought about what happens if you don't move up and shoot. . Either way, I didn't make the calculator suggested adjustments, and I ended up about 5" high.

 

[yo-yo]

You’re certain that 100 is 100 and 200 is 200?

They aren't exact. I think the 100 yard was really about 104 and the 200 was "close", but I didn't ask the exact amount he saw in the range finder. It's a large farm property and the terrain varies a little bit. They should be pretty close though.

 

[yo-yo]

Something is way off.

The only way he'd even get close to 5" high at 200 is with a zero distance of 18-19yds. If he had an 18yd zero, it'd mean his shooting position was 98.37yds above the 100yd target and shooting off the edge of a cliff at a 79.63 degree angle, or the other way around, shooting up towards a target on top of a cliff.

When it comes to shooting the 200yd target though, he'd only be aiming downhill at around a 31 degree angle. Angle compensated horizontal distance would be 170yd.

Agreed. Something is way off. I imagine I was elevated, at most, 10' (3 yards), so I can't imagine that affecting the shot placement by 5" high. Would the bullet even strike above the target in this scenario?
If I was correctly zero'd at 100 yards and then I moved back to 200 yards, AND I was actually 10' feet above the target now (but didn't know it), AND I didn't move the scope turret and simply aimed the scope at the target...would I shoot high? Or low?

BTW - I measured my 1.26" ARC M-Brace scope mount with my scope and I think the actual scope height is closer to 2.5", but I don't think that would matter that much, would it?

 

[misser]

Agreed. Something is way off. I imagine I was elevated, at most, 10' (3 yards), so I can't imagine that affecting the shot placement by 5" high. Would the bullet even strike above the target in this scenario...
If I was correctly zero'd at 100 yards and then I moved back to 200 yards, AND I was actually 10' feet above the target now (but didn't know it), AND I didn't move the scope turret and simply aimed the scope at the target...would I shoot high? Or low?

BTW - I measured my 1.26" ARC M-Brace scope mount with my scope and I think the actual scope height is closer to 2.5", but I don't think that would matter that much, would it?

i can

 

[yo-yo]

some years back shooting a encore 10'' hand gun 762x39 125 gr out to 200 yd. gun zeroed at 100yd .there was elevation change of 20' . 2 targets one ontop of the other, aiming at top target center hitting top target center

Interesting...were you shooting up or down? Are you saying that...with no modification to sights (I'm not well versed in hand guns, but I assume most of them are not scoped with turret adjustments), you hit the center of the 200 yard target - just like you did at 100 yards?

 

[misser]

Interesting...were you shooting up or down? Are you saying that...with no modification to sights (I'm not well versed in hand guns, but I assume most of them are not scoped with turret adjustments), you hit the center of the 200 yard target - just like you did at 100 yards?

not only me but 2 others with me

 

[yo-yo]

i can

Are you saying that the incorrect scope height of 1.5" would play a drastic role in tis scenario, compared to 2.5"? Funny thing is...I didn't use the calculator for any of this....I simply zero'd at 100 yards and then fired at 200, without making any scope turret adjustments. I'm not sure what I would have expected with a small 10' elevation increase above the target, but all of these slight mis-adjustments, seem minimal, compared to a 5" high shot placement, but I don't know for sure.

 

[yo-yo]

not only me but 2 others with me

Interesting. Were you shooting up to the target or down, at 200 yards?

 

[misser]

Interesting. Were you shooting up to the target or down, at 200 yards?

it was down hill

 

[Makinchips208]

I’m thinking there is a gravitational anomaly…

 

[misser]

Are you saying that the incorrect scope height of 1.5" would play a drastic role in tis scenario, compared to 2.5"? Funny thing is...I didn't use the calculator for any of this....I simply zero'd at 100 yards and then fired at 200, without making any scope turret adjustments. I'm not sure what I would have expected with a small 10' elevation increase above the target, but all of these slight mis-adjustments, seem minimal, compared to a 5" high shot placement, but I don't know for sure.

scope height is what it is . so what . i cant get my AR's any closer than 1.5'' .can on the encores,then again so what . the guys shooting a really long ways may have scopes mounted much higher ,even a foot higher but theres a reason for that

 

[misser]

I’m thinking there is a gravitational anomaly…

same thing happens in archery shooting from a elevated stand

 

[yo-yo]

it was down hill

Ok. Interesting.

 

[yo-yo]

I’m thinking there is a gravitational anomaly…

Something is happening here.

 

[yo-yo]

scope height is what it is . so what . i cant get my AR's any closer than 1.5'' .can on the encores,then again so what . the guys shooting a really long ways may have scopes mounted much higher ,even a foot higher but theres a reason for that

Yeah. Interesting. Yeah, I think they need enough downward cant in order to fully utilize the range of the scope, so they need to put the scope up high enough that it doesn't hit the barrel when it's adjusted down for long distance.

 

[yo-yo]

same thing happens in archery shooting from a elevated stand

Ah, interesting. Yeah, I would imagine it would be the same for any projectile path. I wonder how that changes shooting uphill?

 

[spife7980]

Yeah. Interesting. Yeah, I think they need enough downward cant in order to fully utilize the range of the scope, so they need to put the scope up high enough that it doesn't hit the barrel when it's adjusted down for long distance.

The scopes adjustment are all internal, it shouldn’t be moving when dialed once it’s mounted.

 

[CoryT]

Idk. The “problem statement” has a bunch of holes that make me doubt the premise. And, I fully acknowledge that the most likely cause is a zero that is not zero. Perhaps it’s a pedantic point, but height over bore is a necessary variable.

True, but given the ranges and elevation, it would take a mount like that to cause the issue. If that were the case, I doubt the OP would be asking about it here.

 

[hlee]

True, but given the ranges and elevation, it would take a mount like that to cause the issue. If that were the case, I doubt the OP would be asking about it here.

Deja vu?

 

[yo-yo]

Absent a 5"+ high scope mount, if he is in fact zeroed at 100, it's low at 200. Yes, there are two zero points on a trajectory, but with conventional sights and cartridges, the near/far zero at 100 yards is at best 100 - 105. Caliber is not stated, nor is bore height, but a .308 with a factory type scope mount/base might be zeroed at 500 yards, and it would also be on zero at about 11 yards, the initial intersection. I await a ballistic chart showing an off the shelf configuration that would produce a 100 yard initial intersection and a 5" high 200 yard trajectory.

Thanks for your comments here. I missed this one last night while reading through the thread. How are you calculating that? I tried using some basic ballistic calculators, but I can't seem to produce data that suggests two zero points. I think there must really be a plateau at the zero point for this setup?

I am shooting a 6.5 Creedmoor (at 3076 FPS, according to the chrono) with a 120 grain Federal round. I measured the scope height last night at 2.48".

 

[yo-yo]

shooting down hill ?

Just a little bit I think....I think. I don't know how I can tell my relative distance above or below the target, when moving distance back from the target, as the terrain is uneven on the property. I've also wondered how the apps are suppose to account for this. Should I be using the "Shooting Angle" feature? I tried using that afterward, to see if it changed my "Come Up", but it appeared to have almost no effect. Even at extreme amount of angle, like 45-60deg.

 

[yo-yo]

Hmmm, that shouldn’t be 5” high at 200 with any sight height combination. With the rings you mentioned above on a bolt gun you’ll be about 2.25” over

https://jbmballistics.com/cgi-bin/jbmtraj_simp-5.1.cgi

You’re certain that 100 is 100 and 200 is 200?

Yeah, I actually measured it last night at 2.48". It was in the software app at 1.5". I did notice it changed the Come Up from 0.36 MRAD to 0.23 MRAD, when changing the scope height in the app, but that is still nowhere near 5". Interesting.

 

[yo-yo]

The scopes adjustment are all internal, it shouldn’t be moving when dialed once it’s mounted.

Yeah, I didn't state that very clearly. Some of this is hard for me to describe and I'm sure I don't have the proper vocabulary yet. I just meant that I learned I needed an additional 20 MOA (about 6MRADS) on the scope mount, in addition to the 20 MOA on the pic rail, in order to be able to maximize the turret range of the scope, for longer distance. I didn't mean physically moving the scope. Sorry for the confusion.

 

[misser]

Ah, interesting. Yeah, I would imagine it would be the same for any projectile path. I wonder how that changes shooting uphill?

i have only the one time were i shot above my elevation .it was a 129 yd shot on a deer . encore 15'' hand cannon 4570 loaded with black powder ,zeroed at 100 yd. have been told the elevated shot is the same as shooting down hill shot

 

[yo-yo]

i have only the one time were i shot above my elevation .it was a 129 yd shot on a deer . encore 15'' hand cannon 4570 loaded with black powder ,zeroed at 100 yd. have been told the elevated shot is the same as shooting down hill shot

Yeah, that is what I'm wondering...I usually think in extremes, in order to think these things through, and this makes me think of the bullet trajectory being affected differently, when shooting uphill vs. downhill. If you shoot straight into the air (perfectly straight up), vs. shooting straight down (perfectly, from a platform or something).
I was trying to figure out what would happen if you were zero'd at 100 yards and then shot uphill to a target 3 yards above the muzzle elevation. If you didn't make any adjustments to the scope turret, where would that impact the target? High or low? How about if we repeat this, but shooting downhill? Where would that bullet strike?

 

[yo-yo]

I ran some ballistic data that is a bit better than my Hornady app. I had to use a Hornady round instead of Federal, since it wasn't on the list, but I selected a 120 grain from Hornady. It's probably close enough for these purposes. This trajectory is pretty flat at 100 yards. It does appear it's highest elevation is at the target height. Interesting. But, if you let this go out to 200 yards, it should shoot 1.5" low...that's pretty close to what I expected. Either way, 5" high suggests something else completely. Is there a way to us the app to modify uphill/downhill by use of actual elevation, rather than angle? If not, I can do the math and create the angles.

 

[db2000]

Yeah, I saw that, but I just can’t explain how my friends experience could occur over and over again, with different guns, and still have shots at 200 yards hit high. I was shocked myself. I can’t explain it, other than my 100 yard zero must be off.

So you’re saying this happened repeatedly with different guns and your friend was shooting???

 

[yo-yo]

So you’re saying this happened repeatedly with different guns and your friend was shooting???

Yeah. That’s what is the weird part. He bet me I would shoot high, because he does also…with all his guns. That’s what is throwing me off here. I’m an engineer, and I have a general understanding of projectile physics, so I assured him he was wrong. I shot high. He says all his guns do that after sighting them in at 100 yards.

 

[yo-yo]

So you’re saying this happened repeatedly with different guns and your friend was shooting???

I might have to do this all again. Zero at 100. Move to 200 and see what happens. Then, move back to 100. Even consider 75 yard and 150 yard shots to get some additional data. Not sure what is happening here.

 

[wade2big]

I might have to do this all again. Zero at 100. Move to 200 and see what happens. Then, move back to 100. Even consider 75 yard and 150 yard shots to get some additional data. Not sure what is happening here.

Yes. Your zero is way off, your distances are way off, or both. Physics and shit says so. I bet you’ll figure it out.

 

[yo-yo]

Yes. Your zero is way off, your distances are way off, or both. Physics and shit says so. I bet you’ll figure it out.

Yeah, it makes sense mine would be off, but it doesn't make sense that all my friends guns are off too. So weird. I'll redo it and see what happens.

 

[Stev0]

Yes, my scope is above the bore. I haven't actually measured the height, but I'm using a ARC M-Brace mount that's their low mount (1.26") with a 34mm tube scope. I'm wondering if I simply zero'd wrong at 100 yards. I hit the bullseye directly and have a group of about 1/2", so I thought that might be good. Funny thing is...I didn't adjust the elevation knob...I left it alone because of the bet my buddy made me. I expected to shoot low by 1", but I shot high by 5".

Could your buddy have turned your turret while you weren't looking, made a bet with you, & purposely shot his guns high?