Why are my ladder tests backwards (hotter loads hitting lower)?

[Tim Singleton]

this is a pretty good easy to use calculator. input the information for the load. set the heightof scope above bore. start with a lower velocity and go up even if the rifle you input crosses aboe the line of site. as you increase velocity you ca see th flatter path that would show on the target as a lower point of impact

http://handloads.com/calc/

 

[mikecr]

A flatter path doesn't provide lower impact unless the gun is zero'd beyond the range of impacts.

That is, if OPs gun was zero'd at >100yds, and with this he shot a ladder at 100yds, then a flatter path presents lower impacts.
The same happens at EVERY range if you are actually zero'd beyond it.
For instance, if you're zero'd at 400yds, but ladder testing at 300yds, you would see lower impacts at higher velocities.

But it's pretty hard to learn anything, beyond fine tuning with a PB BR gun, from a 100yd ladder.
The answer is to test further out.

 

[Tim Singleton]

A flatter path doesn't provide lower impact unless the gun is zero'd beyond the range of impacts.

That is, if OPs gun was zero'd at >100yds, and with this he shot a ladder at 100yds, then a flatter path presents lower impacts.
The same happens at EVERY range if you are actually zero'd beyond it.
For instance, if you're zero'd at 400yds, but ladder testing at 300yds, you would see lower impacts at higher velocities.

But it's pretty hard to learn anything, beyond fine tuning with a PB BR gun, from a 100yd ladder.
The answer is to test further out.

I think your missing the point. The OP was shooting at 100 yds, he had a velocity increase of 200 fps. With no scope adjustments the impacts will be lower due to the flatter trajectory. it doesn't matter what the scope is zeroed for. for instance the cross hair is on the bull at 100 but the point if imact is 1.5 high for a 300 zero. as the velocity increases and no scope adjustments are made the impact will walk down the target plain and simple

 

[mikecr]

it doesn't matter what the scope is zeroed for. for instance the cross hair is on the bull at 100 but the point if imact is 1.5 high for a 300 zero. as the velocity increases and no scope adjustments are made the impact will walk down the target plain and simple

You just countered yourself here.
It does matter what the scope is zero'd for and your example here puts the zero beyond the test distance(300yd zero for 100yd ladder), just as I stated would be required.

Donovan your graph is showing only that all speeds are still zero'd at 100yds.
They are neither higher nor lower than the 100yd zero -at 100yds.
Now, if he were ladder testing at 90yds, with that 100yd zero, then we can all see what you're trying to illustrate.
I say again, in order for flatter curves to produce lower POI, the actual zero must be beyond the test distance. This is needed to cross the line of sight, as you mentioned to begin.

 

[Tim Singleton]

The scope set point of aim is irrelevant. It is ballistics only. At this close range it really shows up. Think of it like this lock a rifle in a rest no scope on it get it to hit on paper at 100 yds doesn't matter where on paper just on paper. then up the velocity and the trajectory flattens out showing up lower on the paper.

Remember the OP is talking about a high power rifle

I give up after this one

 

[Area Man]

So if I reduce the muzzle velocity to 100 fps, the bullet will go all the way over the target?

Of course not.

If the initial angle of trajectory remains unchanged (the aim point and hold doesn't change) the POI of a faster bullet will always be above the POI of a slower bullet.

 

[Tim Singleton]

So if I reduce the muzzle velocity to 100 fps, the bullet will go all the way over the target?

Of course not.

If the initial angle of trajectory remains unchanged (the aim point and hold doesn't change) the POI of a faster bullet will always be above the POI of a slower bullet.

ok I cant help it. a person really shouldn't post on a subject they know nothing about
take 2 mins to use a ballistics program and think about it before you make a posting you don't understand

it has been said several times the OP is using a high power rifle talking about a velocity change of a few hundred feet per second
if you haven't shot enough to have experienced it for yourself that pretty much explains it

picture in your mind lobbing a baseball at 10 mph to home plate imagine the arc as it travels to home plate now imagine a 100 mph fast ball what does that look like in your mind? is the path of the fastball lower than the slower ball?

http://handloads.com/calc/

 

[mikecr]

Tsingleton, you're wrong.
You shouldn't make blanket statements about it based solely on flatness of trajectory.

Just look at the graph. At any point beyond the intersection of trajectories(~95, 100, 105), POI follows velocity(as OP expected).
At any point before the intersection of trajectories, POI would inversely follow velocity(as OP witnessed -possibly)
So if you just toss the scope & clamp in any ole bore angle, there will still be a point of intersecting trajectories(ZERO), and POI following or not -will be dependent on target distance before or after that intersection(ZERO).

Or if you clamped the bore with zero angle, then path =drop, and drop is directly affected by TOF. So higher velocity=higher impact no matter what there.

 

[Area Man]

ok I cant help it. a person really shouldn't post on a subject they know nothing about
take 2 mins to use a ballistics program and think about it before you make a posting you don't understand

I understand. Someone is contending that a faster bullet impacts lower than slower bullet. All things remaining the same, it just ain't so.

The OP is performing his ladder test without adjusting the sights. He is holding same sight picture and the only thing changing is the bullet velocity (if barrel harmonics are discounted, which I covered in the "initial angle of trajectory is unchanged" caveat). The faster bullet will always impact higher than the slower bullet. Sight height, zero range, etc is irrelevant.

The fact that is being ignored in the ballistic program example is that when the velocity changes, the zero range also changes.

Gravity. It's the law.

 

[Area Man]

picture in your mind lobbing a baseball at 10 mph to home plate imagine the arc as it travels to home plate now imagine a 100 mph fast ball what does that look like in your mind? is the path of the fastball lower than the slower ball?

Does the pitcher release the ball at the same angle to get it to the catcher at 10 mph that he does at a 100 mph?

Of course not. The stipulation of the ladder test is that the release angle is the same.

a person really shouldn't post on a subject they know nothing about

 

[Tim Singleton]

picture in your mind lobbing a baseball at 10 mph to home plate imagine the arc as it travels to home plate now imagine a 100 mph fast ball what does that look like in your mind? is the path of the fastball lower than the slower ball?

Does the pitcher release the ball at the same angle to get it to the catcher at 10 mph that he does at a 100 mph?

Of course not. The stipulation of the ladder test is that the release angle is the same.

I'm not going to debate any further. Some of you who adimately dispute. Please put some range time in at 100 yards with a slower charge then a faster charge. You can debate theory all you would like. I have seen it for myself. So has the OP

 

[mikecr]

You're right Area Man. But the zero range from 100yds doesn't vary much with velocity(+/-5yds).
And Donovan is right about POI relationships prior to zero range -vs- post zero range. He just didn't put it this way.
For OP to see this particular factor means his zero is well beyond 100yds(like 200yds).

 

[Area Man]

You're right Area Man. But the zero range from 100yds doesn't vary much with velocity(+/-5yds).
And Donovan is right about POI relationships prior to zero range -vs- post zero range. He just didn't put it this way.
For OP to see this particular factor means his zero is well beyond 100yds(like 200yds).

Mike. It doesn't matter where zero range is. Zero range changes with velocity.

I can believe in the real world that POI can be lower with a faster bullet, but it is not simple Newtonian physics as is demonstrated in a ballistics program.

 

[Area Man]

I'm not going to debate any further.

In other words, simple Newtonian physics is beyond your comprehension. Maybe you should consider that next time you decide to pipe up with statements to forum members such as " think about it before you make a posting you don't understand"

 

[Tim Singleton]

I'm not going to debate any further.

In other words, simple Newtonian physics is beyond your comprehension. Maybe you should consider that next time you decide to pipe up with statements to forum members such as " think about it before you make a posting you don't understand"

I did think about it and have experienced it.

the OP original conditions 308 win 210 gr berger. VERY important part here 100 yds
2300 fps reference point on 100 yd target
2400 fps .20" lower
2500 fps .28" lower
2600 fps .41" lower

The faster bullets are flatter impacting the 100 yd target lower than the poi of the slower bullet
At some point there is no use in discussing something further.

 

[Area Man]

Whatever the reason, flatter trajectory is not the explanation. When the velocity changes, the zero range changes.

 

[Tim Singleton]

Whatever the reason, flatter trajectory is not the explanation. When the velocity changes, the zero range changes.

I think we really agree on this. The velocity changing the zero is what is happening. He is just not making any scope adjustments. So the zero range change shows itself as a lower impact. The zero becomes say110 yards

 

[ballistic64]

Its physically impossible for a faster velocity to be the cause of a lower impact at a given distance provided the angle of the barrel remains unchanged. Your in some way thinking of line of sight.

 

[Tim Singleton]

we are talking about a ladder test at 100 yards scope with a poa somewhere on a piece of paper at one hundred yards. as the op increased his powder charge the poi in relationship to the original poa is lower. the faster velocity equaling a flatter trajectory at 100 yds prints lower on the target.
I don't know if the 100 yds is a freak occurance because it is so close but I see it with my 6ppc.

if you take the time to in put some data in a ballistic calculator you will see the same thing

 

[lrgoodger]

I see what is happening. Both camps are right here. You just have to define your parameters correctly to understand your results. The ballistic calculator is moving the muzzle position for each speed. That changes the bullet launch angle in order to have the path intersect the 100 yard target. My earlier post clearly stated I was embedding the barrel in a block of concrete, so you can't change the muzzle angle. the path of a bullet coming out of that barrrel with infinite speed will be a straight line with the bore to the bulls eye. The path of any bullet slower than that will be lower on the target. Period.

Now, if you want to get DMoran's paths like in his ballistics chart, you have to break the barrel out of the concrete block so you can tip the barrel up to lob the bullet to the bulls eye. In order to have the line of sight intersect the bulls eye for each bullet speed, you have to adjust the scope back to zero with each bullet speed/ barrel move. The ballistics program paths are correct for what you are inputting, but you have to realize the program makes the presumption that you are changing barrel angle (and therefore bullet launch angle) to intersect the bulls eye at 100 yards.

I fully believe and understand the results you guys say you see at the range. It just takes a little thought to understand what is really happening with the physics of it all.