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Is your aiming accuracy @1000 comparable to one kernel?

Alex Wheeler said:
Talking 1k br with a 6br type case where the really small node is +/- 4 kernels. You dont have to weight to the kernel but you better be +/- 2 kernels. If not you wont be shooting sub 2" vertical. Thats my opinion bases on what I have seen. If 5" of vertical is the goal at 1k, then no you dont need to weigh to the kernel but you also wont be winning a lot.
I would bet if your not "weighing to the kernel" you probably not weighing +/- 2 kernels. Probably more like +/- .1 grain with a beam scale or even worse with the less expensive electric scales. My charge master will tell be I am exactly on the right charge but the lab scale shows it can be off .2 and still tell me Im dead on.
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Well now I guess I will be sucking hind tit this year because I don't have those high dollar scale an have no intention of buying one lol but thanks for you opinion.
 
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steve_podleski said:
you are making a big assumption that velocity is proportional to charge weight.
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Velocity IS proportional to charge weight. That is not an assumption, although I acknowledge that the relationship may not always be perfectly linear. That is really not the issue being discussed here.

However, for the purpose of this discussion, it is not at all a stretch even to make the assumption that the relationship between velocity and charge weight is perfectly linear, because even in non-linear regions of the charge weight-velocity curve, the amount of velocity change induced by the addition or subtraction of a single kernel will still be closely proportional to the average slope of the tangent line within that specific region of the curve. Further, it is more likely that using the assumption the relationship is perfectly linear is the more conservative approach because it is based on a theoretical charge weight-velocity maximal response, i.e. the slope of the best-fit straight line approximation to the curve over its entire range. Within the appropriate range of charge weights typically used for any specific cartridge, it is far more common to observe regions where the slope of the charge weight-velocity curve decreases slightly for short intervals (i.e. flat spots). However, it is not normal or expected to observe sudden and extreme regional increases relative to the slope of the best-fit straight line approximation to the curve over its entire range.

You can split hairs all you want, but what I stated previously is spot on. If you think it is possible to shoot the difference in some minute charge weight whose theoretical maximal effect on velocity is well under the velocity SD of that same load for 5 shot (or more) groups, by all means have at it. The same would be true of trying to shoot the difference with a minute incremental increase in charge weight whose theoretical maximal effect on group vertical was well under the best vertical you could actually shoot for a 5-shot group with that load. It doesn't really matter whether the response is perfectly linear in that region or not. It only matters what the relative response is in that specific region, because the change made will be in an extremely small increment. Whether a specific load was right in the middle of a positive compensation node or well in-between two nodes, the effect of adding or subtracting a single extra kernel of powder on velocity will still be proportional the slope of the tangent line of the charge weight-velocity curve in that same region of the curve. It's not going to suddenly push the vertical response off the cliff, so to speak, and therefore is not the limiting source of error. Nor will it ever become the limiting source of error, unless you're dealing with a response curve that exhibits sudden and extreme non-linear behavior. Charge weight-velocity curves in the regions where loads typically tune in do not normally exhibit such behavior, although you might be able to observe it on occasion at or above MAX pressure, where such sudden and extreme non-linear behavior becomes more common.

It's all about limiting sources of error and statistical analysis, and I can tell you that it is impossible to see some difference on the target with such a small change in charge weight and ever state with any certainty what the actual underlying cause was, i.e. the one kernel change in charge weight. The certainty to which you can ever make such a statement is controlled by the limiting source of error, which in this case is not going to be the effect of a single kernel of powder on velocity. I'm sure there are some that wish to believe otherwise, but simply believing something doesn't make it true.

None of this changes the fact that I am a firm believer of weighing charges as accurately as you possibly can, preferably down to one kernel or less variance. Why? Because if you have a capable analytical balance, it takes little extra effort. Then you know with certainty that charge weight variance is not your limiting source of error, and you can focus your attention on managing the other true limiting sources of error, whatever they may happen to be in your specific discipline.
 
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gstaylorg said:
Velocity IS proportional to charge weight. That is not an assumption, although I acknowledge that the relationship may not always be perfectly linear. That is really not the issue being discussed here.

However, for the purpose of this discussion, it is not at all a stretch even to make the assumption that the relationship between velocity and charge weight is perfectly linear, because even in non-linear regions of the charge weight-velocity curve, the amount of velocity change induced by the addition or subtraction of a single kernel will still be closely proportional to the average slope of the tangent line within that specific region of the curve. Further, it is more likely that using the assumption the relationship is perfectly linear is the more conservative approach because it is based on a theoretical charge weight-velocity maximal response, i.e. the slope of the best-fit straight line approximation to the curve over its entire range. Within the appropriate range of charge weights typically used for any specific cartridge, it is far more common to observe regions where the slope of the charge weight-velocity curve decreases slightly for short intervals (i.e. flat spots). However, it is not normal or expected to observe sudden and extreme regional increases relative to the slope of the best-fit straight line approximation to the curve over its entire range.

You can split hairs all you want, but what I stated previously is spot on. If you think it is possible to shoot the difference in some minute charge weight whose theoretical maximal effect on velocity is well under the velocity SD of that same load for 5 shot (or more) groups, by all means have at it. The same would be true of trying to shoot the difference with a minute incremental increase in charge weight whose theoretical maximal effect on group vertical was well under the best vertical you could actually shoot for a 5-shot group with that load. It doesn't really matter whether the response is perfectly linear in that region or not. It only matters what the relative response is in that specific region, because the change made will be in an extremely small increment. Whether a specific load was right in the middle of a positive compensation node or well in-between two nodes, the effect of adding or subtracting a single extra kernel of powder on velocity will still be proportional the slope of the tangent line of the charge weight-velocity curve in that same region of the curve. It's not going to suddenly push the vertical response off the cliff, so to speak, and therefore is not the limiting source of error. Nor will it ever become the limiting source of error, unless you're dealing with a response curve that exhibits sudden and extreme non-linear behavior. Charge weight-velocity curves in the regions where loads typically tune in do not normally exhibit such behavior, although you might be able to observe it on occasion at or above MAX pressure, where such sudden and extreme non-linear behavior becomes more common.

It's all about limiting sources of error and statistical analysis, and I can tell you that it is impossible to see some difference on the target with such a small change in charge weight and ever state with any certainty what the actual underlying cause was, i.e. the one kernel change in charge weight. The certainty to which you can ever make such a statement is controlled by the limiting source of error, which in this case is not going to be the effect of a single kernel of powder on velocity. I'm sure there are some that wish to believe otherwise, but simply believing something doesn't make it true.

None of this changes the fact that I am a firm believer of weighing charges as accurately as you possibly can, preferably down to one kernel or less variance. Why? Because if you have a capable analytical balance, it takes little extra effort. Then you know with certainty that charge weight variance is not your limiting source of error, and you can focus your attention on managing the other true limiting sources of error, whatever they may happen to be in your specific discipline.
Click to expand...
I fully agree. You have catched the core of my provocative question.
As you said, you can fix @kernel one of the many variables that affect your POI @1000 or long ranges in general, and you will be sure that any issue on the target is not caused by a innacurate powder weight.
But this “kernel” accuracy unfortunately cannot solve many other variables that are almost impossible to control “@kernel” accuracy. Statistics says that a one kernel error (or even more) can be compensated by other fluctuating variables with comparable accuracy’s measurements.
 
Marksman63 said:
I fully agree. You have catched the core of my provocative question.
As you said, you can fix @kernel one of the many variables that affect your POI @1000 or long ranges in general, and you will be sure that any issue on the target is not caused by a innacurate powder weight.
But this “kernel” accuracy unfortunately cannot solve many other variables that are almost impossible to control “@kernel” accuracy. Statistics says that a one kernel error (or even more) can be compensated by other fluctuating variables with comparable accuracy’s measurements.
Click to expand...

I believe this to be true...for any individual non-limiting source of error, although I would use "overshadowed" or "outweighed", rather than "compensated". This is because sources of error in the real world tend be to be additive at a minimum, i.e. the types of error we typically encounter in accuracy/precision don't normally cancel each other out or compensate for one another; they accumulate. Thus, many extremely small sources of error that by themselves, might be essentially undetectable, collectively can add up to a much larger and more noticeable overall negative effect. That is a very different thing than saying it is extremely difficult to definitively identify the effect of a very small (non-limiting) source of error in the presence of much larger sources of error. For that reason, my approach is simple: whenever it is possible to minimize such minor sources of error at a reasonable personal cost by weighing, measuring, metering, dispensing, etc., to a much finer degree than for which I can definitively detect some effect, I will do it.

Other than the time, effort, and potential cost, I do not believe this approach will ever hurt the reloading process in any way in terms of precision, even if there may not be some immediate and obvious gratifying effect on the target. In the long run it will likely pay off and the peace of mind alone is worth much to some individuals. The potential caveat to this approach as I stated before is simply that each individual must determine for themselves how much time and effort they are willing to put into any given reloading step, and then live with the results they obtain.
 
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Alex Wheeler said:
They are less than half the cost of your high dollar bat action. Convince Douglas they need a new scale for weighing buttons or something ;) Then you can borrow it :)
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That's funny Alex I don't care who you are lol PS you don't weigh button just make sure there in size to do the job.
 
This is a great thread! For years I have been fortunate enough to operate a 1000 yard range. I have had many world-class shooters on the firing line over the years. Everything matters at long range. Control as much as you can weigh to the kernel is a must. Remove all excuses. Everyone always wants to know what matters most what is most important in long range shooting. You need good gear but it does not have to be the best the ones that win are the ones that I see on the Range when no one else is there testing their equipment. Winning equals dedication and time spent to perfection. At the end of the day the most important element in the equation of long range shooting will be looking back at you in the mirror.
 
For those cutting kernels in half, you have to be careful. When you do that, you’ve changed the ratio of surface area to weight for that half kernel and it will burn faster than a full kernel. To compensate you have to use about .4 kernels instead of a half.


Yes, if you’re still reading, I’m full of shit. Carry on!
 
My loads come out 62.516 if I take one kernel away it's 62.494! I stay on the high side anyone have a problem with that?

Joe Salt
 
Joe Salt said:
My loads come out 62.516 if I take one kernel away it's 62.494! I stay on the high side anyone have a problem with that?
Click to expand...

Equals a kernel weight of .022-gr.
Myself want under .040-gr max spread.
So by my own standards: "your good to go, with room to spare" !.!.!
Donovan
 
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