HELP WITH SATERLEE VELOCITY TEST

[asd9055]

NW Hunter,
If I went strictly by Satterllee as I understand it, I see three possible nodes. One around 50.7, one around 52.7 and one around 54.1. Being me, I would pick 54.1 and continue following Satterlee steps, without the magneto. Once I settled on load I would play with seating depth to see if I can improve. Again, I am just learning, and for sure I will draw a lot of remarks, but I have thick skin. Also, if you are comfortable at 300 yards, I would work with that. Ot 52.7

Good Shooting!!!
ASD

 

[Bdubose]

My understanding is that the purpose of the Satterlee is to locate a velocity at which one can achieve the lowest ES/SD loads.
I used to begin all my load workups with the Satterlee and found one very important factor:
You can find an excellent velocity node inside a bad harmonic (speed) which makes the load worthless.

Now I do some research on barrel harmonics, and begin my Satterlee test a bit before and after that speed to find the best of both worlds - the flattest velocity node inside the optimum harmonic. If I have to settle for low double digits in ES to keep the load inside the best harmonic range - so be it. FYI: I'm developing for hunting, not Bench Rest.

 

[JASmith]

If it's not clear, OCW/Ladder/Satterlee etc are usually an exercise in interpreting random noise (seeing faces in clouds or reading tea leaves). It's plausible that they may have some merit for the absolutely most precise ammunition and rifles, or perhaps if one were to fire 10 shots at each charge weight to achieve reasonable statistics.

Excellent observation!

That is why one should pick the ponts on the "flat spots" and repeat once or twice. You will likely have a valid node if it repeats a couple of times.

Same for the accuracy tests.

If one's principal range is limited to 100 yards, then choose the 2-3 loads giving best accuracy there and run velocity tests of at least 5 shots for each load. The lowest SD gives one a reasonable change at being accurate at longer range.

Again, repeating the test series helps rule out random noise when looking for the underlying signal.

 

[Opa-lopa]

I've simulated a OCW/Satterlee/Ladder test in the graph below. I used Excel to randomly generate a velocity within the normal distribution one would expect with a muzzle velocity standard deviation of 10 fps. To get the velocity at each charge weight, I took the OP's data and regressed a line through it, which came out to a slope of 55 fps per grain of powder. I then used the OP's 0.2 grain charge increment to calculate the nominal velocity at each increment, applied the random variation, and ran the simulation 4 times.

I circled all the "nodes" for emphasis...

So...see if you can pick out the OP's data from the randomly generated data...

View attachment 207777


If it's not clear, OCW/Ladder/Satterlee etc are usually an exercise in interpreting random noise (seeing faces in clouds or reading tea leaves). It's plausible that they may have some merit for the absolutely most precise ammunition and rifles, or perhaps if one were to fire 10 shots at each charge weight to achieve reasonable statistics.

 

[NeedForSpeed]

My understanding is that the purpose of the Satterlee is to locate a velocity at which one can achieve the lowest ES/SD loads.
I used to begin all my load workups with the Satterlee and found one very important factor:
You can find an excellent velocity node inside a bad harmonic (speed) which makes the load worthless.

Now I do some research on barrel harmonics, and begin my Satterlee test a bit before and after that speed to find the best of both worlds - the flattest velocity node inside the optimum harmonic. If I have to settle for low double digits in ES to keep the load inside the best harmonic range - so be it. FYI: I'm developing for hunting, not Bench Rest.

What research do you do on barrel harmonics and how do you apply it?

 

[Opa-lopa]

So called "Velocity nodes" are wishful thinking, IMO. Here's what happen if you do a hundred replications..

 

[asd9055]

Is this actual data from 100 ladder tests at least 10 rounds each, same rifle, same lot materials? It very interesting if it is.
Or is this simulated data? Just curious. Always willing to learn

 

[asd9055]

What research do you do on barrel harmonics and how do you apply it?

I too look for nodes before I decide what to test, but I won't get into it on an open forum. That would be a new can of worms.
I am planing to try the other method of ladders for POI over 300 yards when the weather cools down.
I try to keep an open mind when many shooters in many forums suggest one method works. I try to understand the physics behind it and then see if I can make it work for me

 

[rgmeddn]

So called "Velocity nodes" are wishful thinking, IMO. Here's what happen if you do a hundred replications..

As a science guy I like the idea of applying statistical tools to all of this. Do you have the statistics expertise to take it further? (I don't but would understand the result!) Statistically how many ACTUAL shooting ladders or tests with how many rounds at each charge would it take to validate (or not) your assumption/conclusion that it is all random statistical noise without actual nodes say to the 95% confidence level? Then the phrase "IMO" becomes N/A.

 

[Stammster]

You got major issues at your case neck in the first picture.

 

[redneckdan]

To the OP.

I use a Satterlee type method as well. I dont always get the most accurate load. I do get loads that hold up well across wide ranging conditions, even with that evil ball powder stuff.

First I run a basic test like you have. I pick out a high node for hunting loads and a lower node for high volume practice. I load a test of each node in .1gr steps 5rds each step and shoot for velocity. These velocities are graphed and the data analyzed. Within that node there is usually a sweet spot. Fine bullet tune might tweak the accuracy a bit more.

I have a load for a savage desert tactical 6 creedmoor with ramshot magnum and the DTAC that shoots with an SD of 4. Off bags it groups around .75" @ 100yds and around 3" @ 600. Why it does better at distance, I don't know. But it has been my experience that loads developed this way dont always do well on the short course but seem to hold together better at range and across changing conditions. And that is what I am after.

I have a load for a savage 12FV with the 69 SMK and 4064 that i developed before i had a chrono and was using the paper target @ 300 and look for clusters method. It always shot really good except in the summer. I finally threw a chrono on it and on a good summer day it has an SD above 50. Once temps get above 80F, it goes nuts. It gets worse with range and higher temps. Both groups are 5 shots. Temps noted. I show this as an example of a reasonably accurate load that is useless to me.

 

[redneckdan]

You got major issues at your case neck in the first picture.

HAHA, LOVE IT!

We're all over here navel gazing and Stammster is the only one to pull his head out of his butt and say 'hey, yer rearranging deck chairs on the titanic here...sucker is goin down'

 

[25WSM]

I've been using the Satterlee method with great success for quite some time. It greatly speeds up load development. It won't replace groups on paper but will get you real close real fast. One thing for sure is if your using a magnetospeed on your barrel don't pay any attention to your group size. Just use it for speed numbers only.
Shep

 

[Quintus]

Well, I combined all the methods at all the distances with and without the magneto from the same lot of powder and brass on my new gun. I found out that I am out of powder, my brass is shot, and I need to re-barrel.