Why are my ladder tests backwards (hotter loads hitting lower)?
- Thread starter josh.rizzo
- Start date
An example with a bore fixed in angle to produce path intersections further than ~100yds, for illustration:
2500ft/sec zero range 421yds 100yd impact = 9.97 600yd impact = -45.93
3000ft/sec zero range 500yds 100yd impact = 8.57 600yd impact = -17.64
3500ft/sec zero range 578yds 100yd impact = 7.47 600yd impact = -2.80
Here, a target placed at 100yds would see lower impacts with higher velocity.
And a target placed at 600yds would see higher impacts with higher velocity.
This applies from any elevating angle of a bore, and therefore can be setup & seen at any range.
2500ft/sec zero range 421yds 100yd impact = 9.97 600yd impact = -45.93
3000ft/sec zero range 500yds 100yd impact = 8.57 600yd impact = -17.64
3500ft/sec zero range 578yds 100yd impact = 7.47 600yd impact = -2.80
Here, a target placed at 100yds would see lower impacts with higher velocity.
And a target placed at 600yds would see higher impacts with higher velocity.
This applies from any elevating angle of a bore, and therefore can be setup & seen at any range.
Tim Singleton
Gold $$ Contributor
I have re read this post from the beginning. It would have been easier to state it this way. take a ballistic calculator set it for 300yd zero 300 yd range select the OP data enter the different velocities then look at the chart as it passes the 100 yd range you will see the flatter bullet path resulting in the faster bullets printing lower at 100
I think we are all in agreement now for the OP as to why his ladder test went down as he went up in charge
I would also like to apologize to everyone for my behavior.
Happy New Year
I think we are all in agreement now for the OP as to why his ladder test went down as he went up in charge
I would also like to apologize to everyone for my behavior.
Happy New Year
It's amazing how stubborn you are 
Truly, most of this discussion has amounted to hijacking of OP's thread. We should have started another.
This is what I've been saying. And it only happens when zero range is beyond test distance(which is not normal for ladder testing).Tsingleton said:
We may be in agreement about one theory, but it is still possible that his barrel is whipping shots for the range of charges, and I'm sure that 100yds is too close for ladder testing.Tsingleton said:
Truly, most of this discussion has amounted to hijacking of OP's thread. We should have started another.
Tim Singleton
Gold $$ Contributor
I guess so
I didn't think the usefulness of a ladder test at 100 was up for debate. Or the fact that the zero was beyond 100
Only that the faster loads printed lower. Looking at a zero further out only demonstrates it to an extreme. The point is he wasn't change the scope adjustments as he fired the faster loads create a different zero
I don't think im the only stubborn one here. That's ok tho
I didn't think the usefulness of a ladder test at 100 was up for debate. Or the fact that the zero was beyond 100
Only that the faster loads printed lower. Looking at a zero further out only demonstrates it to an extreme. The point is he wasn't change the scope adjustments as he fired the faster loads create a different zero
I don't think im the only stubborn one here. That's ok tho
Now I feel like the one being stubborn or dense.
Question to mikecr. Are the zero distances calculated by an equation, or did you input those values into a program?
Because I'm not understanding those numbers. If a target is at 100 yards, and the angle of the barrel is fixed, what happens past the 100 yard point is irrelevant. The travel time to 100 yards varies according to the velocity and the bullet is acted on by the constant acceleration due to gravity. Therefore the slower bullet falls farther because it has been accelerated for a longer period of time than the fast bullet. I think.
All for learning here, and now that debate is settling over the why of lower impacts, can someone explain OP's reported 6 MOA drop? 6 inches at 100 yards is hardly akin to the aforementioned results of a flatter trajectory. I get how lower impacts are possible due to scope height, angle of the barrel and a zero beyond the range of the actual POI, but six inches seems WAY off.
Tim Singleton
Gold $$ Contributor
I was thinking about that earlier when re reading his post
I don't know if the 20 moa base factors in or not idk
I don't know if the 20 moa base factors in or not idk
This one HAS been beat to death, but since I took the trouble on my lunch hour today to create some graphics to assist in this analysis, I'm going to post it. There is no scope or line of sight drawn in any of the three figures because they are IRRELEVANT to the bullet path. These figures and the physics of them would remain true with iron sights or no sights at all provided the gun positioning was stable.
The first figure illustrates, as Area Man says, simple Newtonian physics. The gun does not move (which I was trying to impress with my concrete block earlier) from shot to shot. Bullet velocity and gravity are all that are necessary to prove the faster bullet hits higher, every time at every distance.
The second figure shows what the ballistic program does not. Its job is to show you the bullet path based on speed and CONVERGE each path at the chosen target distance. The program does not tell you what you have to do to get those paths, but my drawing does. You have to alter the muzzle angle to make different velocity paths converge at the same point. I don't think this was what the OP was doing.
The third figure shows how muzzle jump due to recoil can affect bullet impact. I moved the target closer rather than redraw everything, but the point is that the faster, flatter trajectory CAN impact below the slower one because it exits the barrel sooner, when the muzzle is not as high as it was when the slower bullet exited. This is true only at closer ranges as the graph shows.
I understand what has been discussed concerning the line of sight being below the bullet path in some instances and the bullet path going above the line of sight in other instances, but none of that is the CAUSE of where the bullet impacts if the scope is not readjusted between the fast and slow bullets. In the second figure with the paths converging at the target, you not only have to change the muzzle angle to make that happen. If you want the line of sight to be on the bulls eye for each bullet speed, you also have to readjust the scope for each speed.
I also missed the six MOA statement in the OP. Something more was going on there to throw the bullets that low. Nothing that has been discussed in this thread could account for that.
The first figure illustrates, as Area Man says, simple Newtonian physics. The gun does not move (which I was trying to impress with my concrete block earlier) from shot to shot. Bullet velocity and gravity are all that are necessary to prove the faster bullet hits higher, every time at every distance.
The second figure shows what the ballistic program does not. Its job is to show you the bullet path based on speed and CONVERGE each path at the chosen target distance. The program does not tell you what you have to do to get those paths, but my drawing does. You have to alter the muzzle angle to make different velocity paths converge at the same point. I don't think this was what the OP was doing.
The third figure shows how muzzle jump due to recoil can affect bullet impact. I moved the target closer rather than redraw everything, but the point is that the faster, flatter trajectory CAN impact below the slower one because it exits the barrel sooner, when the muzzle is not as high as it was when the slower bullet exited. This is true only at closer ranges as the graph shows.
I understand what has been discussed concerning the line of sight being below the bullet path in some instances and the bullet path going above the line of sight in other instances, but none of that is the CAUSE of where the bullet impacts if the scope is not readjusted between the fast and slow bullets. In the second figure with the paths converging at the target, you not only have to change the muzzle angle to make that happen. If you want the line of sight to be on the bulls eye for each bullet speed, you also have to readjust the scope for each speed.
I also missed the six MOA statement in the OP. Something more was going on there to throw the bullets that low. Nothing that has been discussed in this thread could account for that.
Attachments
mikecr said:
MikeCR, I was reading this thread without knowing the answer myself. I know I have "logic" working on my behalf. However, I still do not know for sure if "my logic" is correct or not. But this I do know... For someone to admit, on this forum, that they may have been mistaken takes a man of honor and integrity! I, for one, think it is very refreshing!
Howdy
Setting “zero†for all to 300 yards then running shooterscalculator at the different velocities clearly indicates that at 100 yards the faster projectile will impact lower.
But will a 24†Savage factory heavy “whip†enough to alone account for the rest of all that vertical at 100 yds?
Setting “zero†for all to 300 yards then running shooterscalculator at the different velocities clearly indicates that at 100 yards the faster projectile will impact lower.
But will a 24†Savage factory heavy “whip†enough to alone account for the rest of all that vertical at 100 yds?
sean68
Silver $$ Contributor
You really need to re-read what LRGoodger has posted. He is absolutely correct in his analysis of this. If you set "zero" at 300 yards the only way to get bullets at different velocities to hit at the same place is to vary the angle of the barrel. The software automatically does this for you when you set the "zero" distance. This is not how you do a ladder test. The point of a ladder test is to hold the gun on the same angle and observe where the bullets hit, not to adjust the gun so the bullets all hit at the same point at one distance and then observe where they hit at another.
What your software is doing would be the same as you constantly adjusting your elevation turret lower each time you increased the speed of the bullet, because that would be the only way you would ever get the bullets to all hit at the same point at 300 yards. Of course the faster ones would hit lower at 100 because they are on a flatter trajectory, BUT that is not what you do in a ladder test. If you adjust the gun for each velocity to force the bullets to hit at the same point the whole test is meaningless.
What your software is doing would be the same as you constantly adjusting your elevation turret lower each time you increased the speed of the bullet, because that would be the only way you would ever get the bullets to all hit at the same point at 300 yards. Of course the faster ones would hit lower at 100 because they are on a flatter trajectory, BUT that is not what you do in a ladder test. If you adjust the gun for each velocity to force the bullets to hit at the same point the whole test is meaningless.
OleFreak said:
I got that early on watching this unfold yesterday and care nothing of what constitutes a proper ladder.
I’m only curious if the muzzle of a barrel the size of a Savage varmint will actually deflect enuf to cause all that vertical spread at 100 yards over what’s already accounted for by the differing velocities.
I’m only curious if the muzzle of a barrel the size of a Savage varmint will actually deflect enuf to cause all that vertical spread at 100 yards over what’s already accounted for by the differing velocities.
No doubt the OP confirmed his “zero†was still something inches high at 100 yards with the known168 gr. loads before all the confusion with the heavies. 
If the remainder of the OP’s 6 MOA vertical difference is all attributable to barrel whip then I had no idea this stuff could ever get that extreme.
If the remainder of the OP’s 6 MOA vertical difference is all attributable to barrel whip then I had no idea this stuff could ever get that extreme.
I agree with you, Ole. I have NEVER seen faster bullets hit lower, but the muzzle jump theory supports the possibility. I think it depends entirely on your bench setup. I've seen times when I had pretty good muzzle jump starting off with a new gun or setup, but I always readjusted everything and added or subtracted stock weight until I got good recoil tracking. I imagine using a bi-pod off a hard bench might cause some issues. Light sporter barrels would be more susceptible as well.
Link
Silver $$ Contributor
I thought I knew the A to the Q of the OP. Now I think I don't know anything.
Does someone with a rail gun experience have any input?
I am pretty sure when I shoot 22lr with a scope zero at 50 feet, it is 3-4 inches high at 150 feet and 3-4 inches low at 300 feet.
Wouldn't that involve line of sight? Would that not relate?
Or does that not pertain?
signed confused.
Does someone with a rail gun experience have any input?
I am pretty sure when I shoot 22lr with a scope zero at 50 feet, it is 3-4 inches high at 150 feet and 3-4 inches low at 300 feet.
Wouldn't that involve line of sight? Would that not relate?
Or does that not pertain?
signed confused.
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