If I may dumb this down for a moment? What is the fastest load development experimental method that will result in a "keeper" load? I have read about the OCW method, Berger seating depth first method, ladder tests, etc.... The kicker is the amount of variables that can be introduced ( primers, powder, cases, bullets, temperature, fouling, reloading variances, etc) I wish that I understood,and could easily use, a fast and repeatable protocol for load development. The method that wasted the least amount of time would be the most interesting to me. I did like the explanation that a "node" may provide some tolerance for a slightly imperfect powder charge, seating depth or other variables.
What is a "Node"?
- Thread starter South Pender
- Start date
Should have clarified that I load for hunting rifles. These are good ones built by competition level smiths, but not bench rifles. For all I know, consistent and better use of wind flags may be the best place for me to start narrowing down the variables. I am tired of wasting time without a consistent and clear load development plan.
Ned Ludd
Silver $$ Contributor
This might be of interest to you:
http://forum.accurateshooter.com/th...ent-using-statistical-design-options.3921946/
Ever thought about how many groups it would take to rigorously determine if one load is better than another? If we shoot the load we have come to like, and say fire several groups with it on a “good” day, we find not all groups measure the same. Take the top five or ten finishers at a group benchrest match and look at all their group sizes. The standard deviation in group size is significant. Given the care taken in the shooting, the variation would have to be considered to be due to uncontrollable variables; the randomness of the process.
With that in mind, we go to the range to find out what charge/seating/whatever is best … we do this with ten or fifteen rounds loaded with each recipe, shoot a few groups and declare one to be best, often without seeing a trend, just one better than others.
Are we kidding ourselves? How many groups does it take to separate the fly specs from the pepper? With the high noise-to-signal ratio in the process, how many groups would it take to prove one load is better than another?
I sometimes wonder if load development and tuning are real except in the minds of the shooters. Don’t know. Just thoughts. Probably gonna start a food fight. I apologize in advance.
With that in mind, we go to the range to find out what charge/seating/whatever is best … we do this with ten or fifteen rounds loaded with each recipe, shoot a few groups and declare one to be best, often without seeing a trend, just one better than others.
Are we kidding ourselves? How many groups does it take to separate the fly specs from the pepper? With the high noise-to-signal ratio in the process, how many groups would it take to prove one load is better than another?
I sometimes wonder if load development and tuning are real except in the minds of the shooters. Don’t know. Just thoughts. Probably gonna start a food fight. I apologize in advance.
CharlieNC
Gold $$ Contributor
You are correct regarding differentiating group sizes. This is one reason using techniques such as ladder and ocw testing which map out the poi movement are much more effective. It's much easier to characterize the average than the variability, which is the methodology of node testing.
Good point. Also, changes that lower velocity variation are beneficial in all probability.
Here's a 1.67 MOA plot of 27 ten-shot groups shot with the same ammo lot:
Which 10-shot group was the smallest? Largest? Are all of their centers at the same place?
What if it was ten 27-shot groups? Or five 54-shot groups? Three 90-shot groups?
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CharlieNC
Gold $$ Contributor
If the different groups were identified there is a distinct possibility that some are significantly different.
How many shots per load in a ladder test are statistically significant?
That's enough to have 90% confidence the spread of all such groups is about 10% in size. It ain't 3.
I equate group shooting to rolling 10 pairs of dice. A 7 on each pair is zero point. They represent the ten main variables dealt with.
That's enough to have 90% confidence the spread of all such groups is about 10% in size. It ain't 3.
I equate group shooting to rolling 10 pairs of dice. A 7 on each pair is zero point. They represent the ten main variables dealt with.
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Interesting that this thread has taken on an 'either or' flavor. With respect to ANY problem, if everyone clings tightly to the status quo because 'it's always worked for me' or 'that's how it's always done', then learning is still-born. The status quo should be the baseline against which any different method or idea is measured. One has to do both. That is how things advance and improve. Just think about how our sport(s) have evolved in the last 20 years. All that came about because folks challenged the status quo, believing they could improve the outcome. Know what? It worked.
With respect to computational (and other types) of models, they are ALWAYS validated with physical testing. That's just the way it's done. Responsibly, anyway.
With respect to computational (and other types) of models, they are ALWAYS validated with physical testing. That's just the way it's done. Responsibly, anyway.
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CharlieNC
Gold $$ Contributor
You are conflating shooting a ladder to map out poi (as in defining a node) using 1 to 3 shots per charge, with trying to map out group size as a response. There are numerous examples on this site by top shooters et al which clearly demonstrate this approach. Think about mapping a chrono response. With one shot each across a charge range its very easy to accurately calculate the velocity at any charge weight within the range. Yet pick any single load to characterize the average velocity and multiple shots are needed to overcome the variability (the number depends on how high is the sd).
Pleeeaaaase, do NOT drop a quarter in that slot!Like with climate models?
You know, I was wondering when that would show up!Sorry, couldn't resist.
Just glanced at this and will read carefully later. Thanks
I've shot enough 20- to 30-shot groups to learn the first through third (or fifth) shot holes' rarely center in that group center. Nor represent where 20 to 30 shots will group.
Craps shooters at the top of their game can quote the odds of throwing snake eyes to boxcars. Very few rifle shooters know the approximate odds of shot counts in a group representing what 95% or more of all such shot-count groups will be.
I am looking ( arguably needlessly) for consistently tight groups, with velocity that safely nears the velocity potential of my chosen cartridge, bullet weight, and barrel length. This is for long range plinking and hunting. Good equipment is involved but it is never heavy benchrest or competition rifles. The shooter, environment, and less robust rifle will always be variables that are difficult to control. I am hoping to find a method that gives me proven accurate loads in the least time possible. I have wasted too much time and bought way too many reloading supplies searching for acceptable loads. I feel that my biggest failure contributing to this waste is a lack of a fixed and repeatable test protocol. Remember that .05 MOA differences in group size are not going to gain me anything practical. I am frankly seeking .25 to .4 MOA loads that are acceptably fast and repeatable. Temp stability is also important to me as I hunt in different environments.
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