Load Development Using Chrono Velocity Ladder

[CharlieNC]

Positive compensation. Often referred to, and demonstrated in an excellent article by Kolbe, exhibiting how a rimfire tuner to properly dial in the harmonic exit time offsets the velocity differences. We use charge weight to accomplish this via a ladder on the target.

 

[JFrank]

Tuning at a known set distance seems to factor into it as well.

 

[CA_Shooter]

I have a friend that has builds out predictive modeling worlds using Artifical Intelligence. This is what he gets paid to do. And it's what he got his PhD in.

I explained the theory of "flat spots" to him and he said the amount of shots we shoot will predict absolutely nothing. Even bringing up the "theory" to him was a bit embarrassing

 

[Doom]

I expected to catch a full ration when I posted the statistical variation simulation and I was not disappointed. No one that I have seen has even posted a plausible theory as why it would exist. Such an explanation is necessary to explain how adding energy in a rifle system can result in a reduction in the increase in velocity or even a reduction as shown on some of the plots.

Now the Father of the One Shot Chronograph Ladder is Scott Satterlee and I have followed his method over time because I quite frankly didn’t buy it. He has changed his load development theory over time. It takes about an hour to go through the two videos but I would encourage people interested in this subject to spend some time with them. The first is the third of a three part series.

 

[Beiruty]

All about tuning using a tuner

Barrel Tuner Analysis -- FEA Dynamic Analysis of Esten's Rifle with/without a Tuner.

 

[CharlieNC]

I have a friend that has builds out predictive modeling worlds using Artifical Intelligence. This is what he gets paid to do. And it's what he got his PhD in.

I explained the theory of "flat spots" to him and he said the amount of shots we shoot will predict absolutely nothing. Even bringing up the "theory" to him was a bit embarrassing

I built predictive models too, and if you understand a little about positive compensation and ballistics then it is not an issue to fit a ladder test shot on a target to the proper harmonic model. But statisticians who do not have the appropriate technology background are not "tuned in" to that understanding.

 

[6bra1k]

charlie
inquiring minds want to know
what do you shoot ?
do you shoot 600 and 1000 yd br ?
have you won at the club level ?
have you won at the national level ?
it's about knowing who to listen to ?
i have shot with alex and tom and a few others on here.
i listen to them because i know what they shoot and how well they shoot.
so what are your credentials in the shooting world ???

 

[CA_Shooter]

I built predictive models too, and if you understand a little about positive compensation and ballistics then it is not an issue to fit a ladder test shot on a target to the proper harmonic model. But statisticians who do not have the appropriate technology background are not "tuned in" to that understanding.

The conversation didn't enter positive compensation, which is irrelevant to the conversation i am pointing out. It is merely about low shot totals NOT being able to come to a statistical significance about a velocity flat spot.

where the bullets ended up or group sizes is outside the realm of that discussion

 

[CharlieNC]

The conversation didn't enter positive compensation, which is irrelevant to the conversation i am pointing out. It is merely about low shot totals NOT being able to come to a statistical significance about a velocity flat spot.

where the bullets ended up or group sizes is outside the realm of that discussion

I agree regarding velocity stats, which was the basis of my original post.

 

[CharlieNC]

charlie
inquiring minds want to know
what do you shoot ?
do you shoot 600 and 1000 yd br ?
have you won at the club level ?
have you won at the national level ?
it's about knowing who to listen to ?
i have shot with alex and tom and a few others on here.
i listen to them because i know what they shoot and how well they shoot.
so what are your credentials in the shooting world ???

Why are you concerned about shooting credentials vs logical discussion? Or who I shoot with?

Have I stated something you wish to question which contradicts your beliefs? I hope so because that is how we learn and progress.

If you are really that interested in me I am happy to engage in a pm to discuss.

 

[INTJ]

I think we have a couple different meanings for "positive compensation".

If we mean the idea that bullets can shoot tighter MOA at longer ranges, Bryan Litz tested that extensively and found it wasn't so. That tracks with what I have seen shooting groups on paper at 100, 200, 300, 385, 600, and 1000 yds.

However, if by "positive compensation" we mean that we can tune barrel harmonics to a wide enough node so that slightly higher powder charges impact lower that slightly lower powder charges at say 1000 yds, then I think that is real. I have seen this repeatedly as have dozens of other 1000 yd BR shooters. We in fact tune to find that.

 

[6bra1k]

let's start with your opening assumption is in error. you have no proof that a process that has been in use for over 70 years is somehow no longer used by intelligent shooters. zero PROOF for your OPINION. HOW IS THAT FOR LOGIC.
ANSWER THE QUESTION
i do not take input from the VIEW and i will not take input from anyone on this forum without "creds".
shooting is not logic ..it is a sport with many variables. you seem to have missed that very basic point
bye

 

[INTJ]

let's start with your opening assumption is in error. you have no proof that a process that has been in use for over 70 years is somehow no longer used by intelligent shooters. zero PROOF for your OPINION. HOW IS THAT FOR LOGIC.
ANSWER THE QUESTION
i do not take input from the VIEW and i will not take input from anyone on this forum without "creds".
shooting is not logic ..it is a sport with many variables. you seem to have missed that very basic point
bye

Mike,

No one is forcing "input" on you. We are just a bunch of enthusiasts discussing stuff we are interested in. Take it for what it's worth and don't read too much into it.

 

[CharlieNC]

Mike,

No one is forcing "input" on you. We are just a bunch of enthusiasts discussing stuff we are interested in. Take it for what it's worth and don't read too much into it.

That was the basis my opening question, asking to see a "thorough" study of a procedure which was hot and then it was not. But apparently that view is logic instead of sport.

 

[Beiruty]

Food for thoughts:
Can anyone explain while shooting 3-5 shots groups on the ladder, the SD and ES are singnficantly lower for a given charge?

 

[JFrank]

I expected to catch a full ration when I posted the statistical variation simulation and I was not disappointed. No one that I have seen has even posted a plausible theory as why it would exist. Such an explanation is necessary to explain how adding energy in a rifle system can result in a reduction in the increase in velocity or even a reduction as shown on some of the plots.

Now the Father of the One Shot Chronograph Ladder is Scott Satterlee and I have followed his method over time because I quite frankly didn’t buy it. He has changed his load development theory over time. It takes about an hour to go through the two videos but I would encourage people interested in this subject to spend some time with them. The first is the third of a three part series.

I don’t use Scott’s system because I can’t understand it, however I can grasp how rounds can impact the same vertical plane despite the increase in power.

 

[Doom]

Food for thoughts:
Can anyone explain while shooting 3-5 shots groups on the ladder, the SD and ES are singnficantly lower for a given charge?

Without getting into a long drawn-out explanation of the statistics and probability, when you measure only three or five shots that is a high degree of uncertainty in what part of a higher population you are testing. when we test anything we don't compare the test results between the tests until we apply a confidence interval to each test and compare the test on that basis. The graph below was based on some data in a different thread that tested three shots at 2707 mean velocity and a 4.74 SD. The 95% confidence interval is shown for 3,5,10,20, and 30 rounds. That is, we can only estimate that the true mean of a population (large number rounds loaded the same) will be within that range. When we load 3 or 5 rounds with different charges and test and say the SD is different from the test data without analyzing the variance (SD) we do not actually know whether they are different or not.

I hope this helps.

 

[David Milisock]

Proponents of a single shot chrono ladder seem to have fallen out of favor due to the insufficient statistics, but wondering if anyone has tried this using a "valid" number of shots to find anything informative? Im trying to stay open minded.

I run 5 shot chronograph tests, shooting groups through the clock. I pick warm days and may take 10 loads with me, repeating the process possibly several times. I'm concerned about pressure safety. I write down the peak load and the best grouping loads and rarely chronograph the loads again. I work loads between the tested charge weights until I find a compromise that works, knowing how the loads clocked and the charge weights I do have an idea of velocity and many times the chosen load was one I clocked.

Varmint work almost always requires a compromise between best group and velocity. In my case there's no more than an 1/8" change in the group at 300 yards but many times 400 to 600 FPS difference which is huge in a world of terraced farm fields and no wind flags.

Once I pick my load I load up all the supplies I have of the same manufacturer lot. I shoot a center hold at 50 yard increments out to 600 yards write the trajectory down and start the process again when the bullets get low.

 

[Beiruty]

@Doom

Please can you have look at this load development?

300 WM 225gr ELD-M H1000 load development.xlsx

1drv.ms

Note at 76gr the SD shrunk dramatically.

 

[Orr89rocz]

Food for thoughts:
Can anyone explain while shooting 3-5 shots groups on the ladder, the SD and ES are singnficantly lower for a given charge?

Not sure but i see it all the time and my guess is something about the nature of explosives, the pressure rise, burn rates in the powder used. I just loaded a 308 last night, and 3 of each charge from 47.5 to 49.5 in half grain steps. Not exactly a ladder 0.2 or so increment described in this thread but this is what i saw

Numbers arent necessarily in order of shots
47.5 2804 2811 2824
48. 2850 2838 2865
48.5 2881 2875 2892
49. 2906 2879 only 2 here didnt get 3
49.5 2945 2935 2937

So seems there’s something goin on at 47.5 thats pretty happy imo. 48.5 may be close too. Could try a few tenths change either way. 49.5 looks pretty ok. Levels abit there and i’ll likely pursue that charge and do seating and chrono that too

300 win mag test i did. 2 shots
1: 73.5 2772 2722
2: 74 2766 2793
3: 74.5 2812 2826
4: 75 2827 2830
5: 75.5 2876 2853

The range in 74.5-75 looks good. So i did 74.8 heres the next 12. 4 diff seat depths however but fairly consistent. So the concept seems to work well for finding a tighter es spread
2824 2827 2832 2826 2842 2798 2829 2842 2838 2805 2823 2828