RustyRick
Well-Known Member
At 330 yrs (24 X scope, bench & sand bags) what kind of elevation/vertical would youz considered a NODE?
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NODES _ Ladder test
- Thread starter RustyRick
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RustyRick
Well-Known Member
When I've done ladder tests at 250 yards a good vertical node is less than half and inch.
I'd expect considerably less than an inch at 330 yards but have no direct experience at that distance.
I think you mean MORE. The farther out you go the more exasperated it will be.
If you shoot two shots with each load, will they go into the same respective hole as the first one did and have the same vertical separation?
In other words, does that one shot of each load represent where all rounds of that load will go?
In other words, does that one shot of each load represent where all rounds of that load will go?
RustyRick
Well-Known Member
I've been using .5 grn for my 7MMRM, and .3 grns for my 243.
What I meant earlier is that a 1/2" vertical height at 250 will be a bigger spread at 330. So one can really fool himself if he works of a too large a spread closer up.
The goal would be 0" spread.
So my question is, if I have say a 1.5 inch spread at 330 is that worth working with.
What I meant earlier is that a 1/2" vertical height at 250 will be a bigger spread at 330. So one can really fool himself if he works of a too large a spread closer up.
The goal would be 0" spread.
So my question is, if I have say a 1.5 inch spread at 330 is that worth working with.
Sierra Bullets' software calculates the following bullet drop difference for charge weight increments at different ranges as shown assuming the bore axis is exactly the same angle above the horizontal for each shot:
6mm 100 gr. SBT @ 2850 fps, 3/10ths grain charge weight change of IMR4064 has a muzzle velocity change of 21.4 fps and the drop difference at:
200 yards = .150"
300 yards = .363"
400 yards = .699"
500 yards = 1.20"
7mm 160 gr. SBT @ 3050 fps, 5/10ths grain charge weight change of RL19 has a muzzle velocity change of 21.7 fps and the drop difference at:
200 yards = .120"
300 yards = .285"
400 yards = .530"
500 yards = .885"
What accuracy level does each load have to have at those ranges so a single shot from each load is meaningful in where it strikes in elevation?
What if that shot's the highest one in a group of several with that load? Or the lowest one?
I don't think one shot of a given load has any meaning down range unless that load's accuracy is no more than 1/3rd the drop difference in the lists above.
Can anyone explain why a single shot is statistically significant considering all the variables in the ammo, rifle and shooter cause bullets not to go into the same hole or vertical position at any range?
Has anyone repeated the same test to see if the same results are given?
6mm 100 gr. SBT @ 2850 fps, 3/10ths grain charge weight change of IMR4064 has a muzzle velocity change of 21.4 fps and the drop difference at:
200 yards = .150"
300 yards = .363"
400 yards = .699"
500 yards = 1.20"
7mm 160 gr. SBT @ 3050 fps, 5/10ths grain charge weight change of RL19 has a muzzle velocity change of 21.7 fps and the drop difference at:
200 yards = .120"
300 yards = .285"
400 yards = .530"
500 yards = .885"
What accuracy level does each load have to have at those ranges so a single shot from each load is meaningful in where it strikes in elevation?
What if that shot's the highest one in a group of several with that load? Or the lowest one?
I don't think one shot of a given load has any meaning down range unless that load's accuracy is no more than 1/3rd the drop difference in the lists above.
Can anyone explain why a single shot is statistically significant considering all the variables in the ammo, rifle and shooter cause bullets not to go into the same hole or vertical position at any range?
Has anyone repeated the same test to see if the same results are given?
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Bart you seem like a very experienced knowledgeable shooter
What I find is that I will find an accuracy node where sometimes a full grain or more of powder change will have nearly the same POI and .3 of a grain above or below that charge has a large change in POI.
What causes this. Theoretically according to your table that change should be linear.
I like those large nodes because then I know variation as much a a 0.5 grains won't effect the groups so much.
Strange thing is it will show up in your es and sd but not so much in your group.
What I find is that I will find an accuracy node where sometimes a full grain or more of powder change will have nearly the same POI and .3 of a grain above or below that charge has a large change in POI.
What causes this. Theoretically according to your table that change should be linear.
I like those large nodes because then I know variation as much a a 0.5 grains won't effect the groups so much.
Strange thing is it will show up in your es and sd but not so much in your group.
It won't be linear with range; physically impossible. The bullet slows down and drops more for each 100 yard increment of range.What causes this. Theoretically according to your table that change should be linear.
It won't be linear with range; physically impossible.What causes this. Theoretically according to your table that change should be linear.
The bullet slows down and drops more for each 100 yard increment of range. For example, the 7 Rem Mag's bullet drops .16 inch (.16 MOA) in the first 100 yards; in the last 100 yards from 400 to 500, it drops 2.32 inch (.464 MOA). Time of flight over the last hundred yards is greater than the first hundred.
I'll get a spreadsheet made to show the data.
It won't be linear with range; physically impossible.
The bullet slows down and drops more for each 100 yard increment of range. For example, the .243's bullet drops .16 inch (.16 MOA) in the first 100 yards; in the last 100 yards from 400 to 500, its drop difference is 2.32 inch (.464 MOA) compared to 3.26 inch more to 5.58 inch (1.12 MOA) difference at 500. Time of flight over the last hundred yards is greater than the first hundred.
I guess I didn't explain myself well. I mean drop with different powder charges. keep it simple.
I know the bullet is falling and that fall is accelerating at roughly 32 feet per second per second. the longer it is in the air the slower the horizontal velocity and the faster the vertical velocity. Then throw in wind resistance and you get a very complicated equation.
