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200 Yards Ok to Run a Ladder?
- Thread starter MMH
- Start date
How far are you intending to shoot? If you are trying to determine which charge weights are going to group together best, just bear in mind that even a 50 FPS difference in your 6.5 CM is going to only produce .2 inches difference in trajectory at that distance. Basically, the dispersion of your groups are going to be greater than that and skew any results you think you might be seeing.
If you are going to keep the majority of your shooting under 500, you can probably use those components better in other ways.
If you are going to keep the majority of your shooting under 500, you can probably use those components better in other ways.
+1 with diggler1833
Simple answer is no. At 200 yards the trajectory is still very flat and the shotfall pattern is not developed.
ETA: You can get a heated debate going on a forum about the whole concept of a velocity/charge node and if this exists or not.
This is due to the fact that many rigs are so stiff that those secondary harmonics are negligible and of little or no consequence. That isn't bad news, but it also doesn't mean a test isn't a good idea for an unknown rifle pattern because in some rigs those harmonics matter.
To answer the question of how far this needs to be to make the results viable isn't an easy question. Think of these factors, the typical short range dispersion of the rifle, the theoretical effect of the trajectory due to velocity and velocity changes.
For example, if a rig has a 1 MOA dispersion at 200 yards, and the trajectory math says that a whole charge range for the ladder doesn't change the elevation more than 2 inches at that distance, the signal to noise in that test means you probably can't see anything useful.
Now, shoot that test out where the elevation change for the speed range of the test is at least double the dispersion, and you have a chance.
A typical 6.5 CM with a Berger 140 Hybrid doing 2400 to 2600 fps, has 600 yard drops of 18 to 15 MOA.
That is only a 3 MOA climb in the whole ladder at 600 yards, so a 1 MOA rifle has a low chance of "seeing" something, while a 0.5 MOA rig can see it if it is there.
That same test at 200 yards only spreads about 0.5 MOA in vertical.
Simple answer is no. At 200 yards the trajectory is still very flat and the shotfall pattern is not developed.
ETA: You can get a heated debate going on a forum about the whole concept of a velocity/charge node and if this exists or not.
This is due to the fact that many rigs are so stiff that those secondary harmonics are negligible and of little or no consequence. That isn't bad news, but it also doesn't mean a test isn't a good idea for an unknown rifle pattern because in some rigs those harmonics matter.
To answer the question of how far this needs to be to make the results viable isn't an easy question. Think of these factors, the typical short range dispersion of the rifle, the theoretical effect of the trajectory due to velocity and velocity changes.
For example, if a rig has a 1 MOA dispersion at 200 yards, and the trajectory math says that a whole charge range for the ladder doesn't change the elevation more than 2 inches at that distance, the signal to noise in that test means you probably can't see anything useful.
Now, shoot that test out where the elevation change for the speed range of the test is at least double the dispersion, and you have a chance.
A typical 6.5 CM with a Berger 140 Hybrid doing 2400 to 2600 fps, has 600 yard drops of 18 to 15 MOA.
That is only a 3 MOA climb in the whole ladder at 600 yards, so a 1 MOA rifle has a low chance of "seeing" something, while a 0.5 MOA rig can see it if it is there.
That same test at 200 yards only spreads about 0.5 MOA in vertical.
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My goal is to develop 1000 yard loads.
Even at 500 yards a 50 FPS variation results in 2.5" difference in trajectory (1/2 MOA). At shorter distances will measuring velocity be meaningful for finding a load that will have most stable velocity (i.e. least sensitive to charge variation). I would measure velocity with LabRadar.
Even at 500 yards a 50 FPS variation results in 2.5" difference in trajectory (1/2 MOA). At shorter distances will measuring velocity be meaningful for finding a load that will have most stable velocity (i.e. least sensitive to charge variation). I would measure velocity with LabRadar.
Looking for a stable velocity will tell you how well you're producing cartridges that are consistent at whatever powder charge you use. Depending on the case fill, ignition can have significant variation.
Go by what you're able to get on target. The further out you shoot for load development the more weather report you'll get. To avoid that, be sure you test when there's no wind or very very little wind. I like to do my load development at 100 yards to keep that weather report to minimum. Once I've found good results, then I'll test it out at distance and then make any additional adjustments that might be needed.
. . . just some of my thoughts for you to consider.
I like to do centerfire testing at 3-400. Far enough to actually see visually on paper what is happening and how changes impact downrange. I believe most concerns about wind are exaggerated at these ranges. I test 22LR at 200 and it is not difficult to stay on paper. If the wind is gusty, don’t make sweeping load decisions based on horizontal spread. Wind’s impact on the vertical is very small at 3-4 for non BR shooters.
No, measuring velocity doesn't tell you where the load is tuned, only the target can tell you this.
There is average velocity, and then there is velocity spread. You don't gain from a poor velocity stat, but the idea of tuning a load for pre-loaded ammo is not done by watching chronographs, it is done by focusing on the target data.
That is not to say you shouldn't measure your velocity and use that information to help select components and close loop on your workmanship and cleaning, but avoid the concept that there are "velocity flat spots".
These "flat spots" evaporate once enough samples are used. We do however want to avoid really poor SD/ES issues that indicate problems with ignition, workmanship, cleaning issues, poor materials, etc.
A chronograph is critical for learning about your workmanship and the recipe. It also tell you about climate effects and cleaning. So while it is important and very useful, it doesn't lead the load tuning in the way many folks assume it does.
If all you have is 500 yards at home base, but you plan on competing at 1000, there is no way to call it anything but a disadvantage. However, you are not the first or last who has no access to full distance. Use what you have and do everything you can to get the 500 yard performance down. There can and will be effects that show past 500 that you can't anticipate, but you can still compete.
There is average velocity, and then there is velocity spread. You don't gain from a poor velocity stat, but the idea of tuning a load for pre-loaded ammo is not done by watching chronographs, it is done by focusing on the target data.
That is not to say you shouldn't measure your velocity and use that information to help select components and close loop on your workmanship and cleaning, but avoid the concept that there are "velocity flat spots".
These "flat spots" evaporate once enough samples are used. We do however want to avoid really poor SD/ES issues that indicate problems with ignition, workmanship, cleaning issues, poor materials, etc.
A chronograph is critical for learning about your workmanship and the recipe. It also tell you about climate effects and cleaning. So while it is important and very useful, it doesn't lead the load tuning in the way many folks assume it does.
If all you have is 500 yards at home base, but you plan on competing at 1000, there is no way to call it anything but a disadvantage. However, you are not the first or last who has no access to full distance. Use what you have and do everything you can to get the 500 yard performance down. There can and will be effects that show past 500 that you can't anticipate, but you can still compete.
I measure and look for tight velocities at 100 when I do initial load development. ES and SD has to be tight at 100 for me to consider it worthy of shooting further...even if the groups look good.
In my experience single-digit SDs usually translate to very tight vertical dispersion past 500. If you end up with SD's in the teens just because that 100 yard group looked good, that means ES is probably going to be ~50 FPS - and you'll add an extra 1 MOA vertical at 1K yards.
PRoblem is that to get meaningful SDs you need to shoot 10 rounds. 10 rounds per charge is a lot!
