3 shot group vs ladder tests

[Varminterror]

I realize that was not your data, but feel you are missing the whole point...the scores were all clean and there were no velocities indicated on the scoring sheet. For there to be 3 clean targets in a row then the rifle, load development and shooter were more than adequate as the score sheet confirms.

You’re missing the point that this score was not earned on the back of picking velocity based on a flat spot, and rather demonstrably, was earned in spite of wasting those rounds to choose the load through that method.

(You also may not have noticed it was not 3 cleans in a row, but rather occurred on different dates).

This is a classic appeal to authority argument, and the classic Post hoc ergo propter hoc fallacy - “this happened, so it must have happened because of that.” No argument that the dude can shoot, no argument that the load holds together, but there’s strong evidence that the flat spot in the velocity curve is not why he shoots well.

 

[ballisticdaddy]

You’re missing the point that this score was not earned on the back of picking velocity based on a flat spot, and rather demonstrably, was earned in spite of wasting those rounds to choose the load through that method.

(You also may not have noticed it was not 3 cleans in a row, but rather occurred on different dates).

This is a classic appeal to authority argument, and the classic Post hoc ergo propter hoc fallacy - “this happened, so it must have happened because of that.” No argument that the dude can shoot, no argument that the load holds together, but there’s strong evidence that the flat spot in the velocity curve is not why he shoots well.

I apologize for my oversight as well as my utter ignorance in this matter. Apparently I just stumbled into a high master classification by not earning all of those scores that I shot due to settling on some unsubstantiated velocities. In the future I will only post those scores that were honestly earned through endless graphs, statistics and detailed spreadsheets. Silly me thought shooting competition was really all about marksmanship, reading wind and all that other nonsense that one has to deal with outside of a clean room environment.

 

[LVLAaron]

I'm sorry I noticed my flat spots. I'll be sure to tell myself I'm wrong.

 

[Varminterror]

^ This is more of the repeated post hoc ergo propter hoc x appeal to authority fallacy.

If you’re claiming the flat spots in the velocities are truly differentiated - truly repeating flat spots - then it seems as though it should be simple enough to provide defensible evidence that they do repeat.

But when it takes under 2min and a cell phone photo editor, with no actual mathematical analysis to defeat the indefensible evidence, is it really evidence?

I didn’t ask for any “clean room” or “barrel burning volume of data,” I simply pointed out that the inherent noise to the load influences whether we can trust where individual shots fall within a data set in a velocity curve. The guy posted a curve with less than 30 ES between all shots, and showed data for 20 rounds which gave 13-14SD, which would correspond to something around 55-60 ES… so within the center ~20-30fps error band, roughly +/-1SD for the same exact load, we can’t pretend all of the shots are EXACTLY their given value, and have to acknowledge that all of those shots within that 13 or 14fps SD load were exactly the same, despite that big difference in velocity.

So we know we have inherent error of +/-13.14fps as standard, as high as +/-30fps error demonstrated, but we pretend when we see a flat spot which is a missed carry of 3-4fps, it must be meaningful… that doesn’t make any sense, right?

 

[CharlieNC]

I'm sorry I noticed my flat spots. I'll be sure to tell myself I'm wrong.

Given the velocity SD of any given charge weight, you can truly see anything you want to see between small charge weight differences. But it is perhaps surprising that this is not the situation on the target where the point of impact response is much more consistent and reliable.

 

[JFrank]

Too funny’’
My rifle can’t read the data and neither can I, so we just look at the target.

 

[LVLAaron]

If you’re claiming the flat spots in the velocities are truly differentiated - truly repeating flat spots - then it seems as though it should be simple enough to provide defensible evidence that they do repeat.

I never said that. In the case of the WSM... I simply found a good load, and graphed the data as an after thought, and have upset the internet because there's a flat spot. I simply find it interesting. I'm not advocating for it or challenging any amount of statistics. But I still haven't seen anyone elses targets.

 

[quest450]

Too funny’’
My rifle can’t read the data and neither can I, so we just look at the target.

I was gonna ask somebody to translate what the Vermin dude was saying......I know ESL

 

[Varminterror]

it is perhaps surprising that this is not the situation on the target where the point of impact response is much more consistent and reliable.

just look at the target.

Bingo.

If we run out the potential influence of velocity relationship to charge weight versus the potential induced error on target, we can see the perceived flat spots just aren’t the reason small groups hold together at distance. Compounding errors just don’t work that way. +/-15fps on a 6 Dasher should be about 6” of induced vertical at 1k based on velocity alone. But that doesn’t happen. Why? Because the errors don’t add, so our sensitivity to velocity isn’t what the ballistic engine might lead us to believe.

 

[CharlieNC]

Bingo.

If we run out the potential influence of velocity relationship to charge weight versus the potential induced error on target, we can see the perceived flat spots just aren’t the reason small groups hold together at distance. Compounding errors just don’t work that way. +/-15fps on a 6 Dasher should be about 6” of induced vertical at 1k based on velocity alone. But that doesn’t happen. Why? Because the errors don’t add, so our sensitivity to velocity isn’t what the ballistic engine might lead us to believe.

You actually observe the target flat spot due to positive compensation associated with measurable muzzle harmonics, which are additive with the ballistic velocity effect.

 

[tom]

Bingo.

If we run out the potential influence of velocity relationship to charge weight versus the potential induced error on target, we can see the perceived flat spots just aren’t the reason small groups hold together at distance. Compounding errors just don’t work that way. +/-15fps on a 6 Dasher should be about 6” of induced vertical at 1k based on velocity alone. But that doesn’t happen. Why? Because the errors don’t add, so our sensitivity to velocity isn’t what the ballistic engine might lead us to believe.

they go where they go is my conclusion after seeing countless groups with higher es have less vertical than the lower es cousin shot in the same series. Below is a true "ladder", and either the crony lies or......just trust the holes!



Tom

 

[tom]

Follow up a week(ish) later with a whopping 2 shot (groups).



Ladders do work, and we don't need 50 shot groups to get where we're trying to go.

Tom

 

[FTR_Mojo]

Bingo.

If we run out the potential influence of velocity relationship to charge weight versus the potential induced error on target, we can see the perceived flat spots just aren’t the reason small groups hold together at distance. Compounding errors just don’t work that way. +/-15fps on a 6 Dasher should be about 6” of induced vertical at 1k based on velocity alone. But that doesn’t happen. Why? Because the errors don’t add, so our sensitivity to velocity isn’t what the ballistic engine might lead us to believe.

I've really enjoyed reading your responses to all this. For me at least you've made it all make a lot more sense. Thanks for taking the time to do that. I really appreciate it.
I really tried to fund flat spots in my velocity data. But it always ended linear. Or the flat spots were very subtle. So I gave up worrying about that.

Now I shoot 3 or 5 shot groups and do the usual, which is look for 3 sequental groups of similar POI and thats my starting point for further charge testing. Etc. I never do single shot testing for anything really.

I guess thats what's fun about shooting precision. One persons nightmare method is another person's dream, but they both have top performing rifles. Go figure.

 

[jelenko]

I'm sorry I noticed my flat spots. I'll be sure to tell myself I'm wrong.

How many shots do you take to show the 'flat spots'?

 

[JFrank]

Follow up a week(ish) later with a whopping 2 shot (groups).

View attachment 1673968

Ladders do work, and we don't need 50 shot groups to get where we're trying to go.

Tom

Tom, are you bringing that orange gun to the Nat’s ?

 

[tom]

Tom, are you bringing that orange gun to the Nat’s ?

Still working on it, gonna shoot 3 whole shot groups Friday at the July matches!
But likely it will be with me yes.
Tom

 

[Old Navy]

I lost track of this p***ing match. Who won?

 

[rabbit fingers]

Can't the same logic be applied to the point of impact as well? With a statistically valid sample size Do Small changes in charge weight or oal REALLY effect where a bullet lands? Where/when did the idea that charge weight had an effect on group size? Couldn't it be more to do with consistency than the actual charge weight?

 

[old_heli_logger]

You actually observe the target flat spot due to positive compensation associated with measurable muzzle harmonics, which are additive with the ballistic velocity effect.

There it is! Positive compensation...

 

[LVLAaron]

How many shots do you take to show the 'flat spots'?

When starting with a completely unknown cartridge, I'll load a "ladder" of 10 rounds. .2 or .3 increments. I shoot groups of 3 and see what looks good and work from there.